Weddingbee boards

Ha :) Yeah they can all look the same.  Basically, the things that distinguish black dinner jackets from generation to generation are the lapels, number of buttons on the jacket and the accessories (bowtie vs. straight tie, vest style/color, cummerbun color, shirt style etc.). All your questions about tux differences are answered at the Blacktieguide.com website (check out the section on Vintage Weddings too):

http://www.blacktieguide.com/History/06.htm

Nothing too distinct about post-war 1940s tuxedos. They were still doing traditional black tie, but the lapels were a bit wider than the trimmer looks of the 50s and today. If you want it to be 1940s, make sure he's either in a cummerbun or that the vest is very low, like this one below. And he definitely needs to be in a bowtie if you want it to look 40s inspired. The long tie did not become a tuxedo accessory until the 1990s. And I don't want to kill your buzz but his vest/tie would need to be black if you wanted the tux to look anything like it was from the 1940s. Matching colors would not have happened until maybe a hip wedding in the 70s and then conventional in the 80s/90s/today.

If you'd like further 1940s inspiration here are two advertisements for 1940s wedding attire in Esquire:

Early 40s:

http://www.blacktieguide.com/Vintage/Vintage%20illustrations/Wedding/1942_May_Esq_p77,78_pullout_sweetened.jpg

Late 40s (double-breasted suits came back when the war was over... they had been banned as part of the rationing efforts):

http://www.blacktieguide.com/Vintage/Vintage%20illustrations/Wedding/1948_Jun_Esq_p86.jpg

As I said, the lapels were bigger and they were still following the classic black tie rules in the 1940s. So if he's in a tux, he would need to be in shawl or peak lapels. Don't go crazy with the boutonniere. Slap on a bowtie (unless it's the formal version of the tux and you go tails and ascot). Go with a black cummerbun (finding a vest low enough to be considered "classic" is hard these days.) 

And then do his hair like Rhett Butler and you're set ;)

@Statutory Grape: Ha! I was jokin' about the hair ;)  I'd just stick to what he knows best, unless he really wants to get into the vintage thing.

So how important is the vintagey look to you guys? Is this a wedding theme for the decor/dresses/etc.? He will look fine with the grey vest. It's very popular and guys look smashing in it. But that puts you in a pickle: how to add a grey vest and maintain a vintage feel. On a black dinner jacket, when you introduce color to the waistcoverings or the tie, you head down the modern road since the only widely acceptable colors for accessories were white, black and this deep red/burgundy color that looked black in the dark. But you don't live in the 40s---you live here and now and being present is perfectly fine. That's why I ask, though. If it's imperative that he goes full-blown vintage 40s, then I'd stick to the guidelines on those links regarding 40s black-tie. Grey vests would only appear on formal morning dress

I can't stress this one enough, though: if you put him in a 2 or 3 button notch lapel jacket and a straight tie with his grey vest----that will obliterate any nod to the traditional look of 1940s. So maybe you guys only want the jacket to be classic: so go with peak/shawl lapels on a one-button jacket. Get grey accessories and call it a day. Classic jacket with modern accessories. I think that would look great. Also, if he goes with a bow-tie instead of a straight tie, it will feel a lot more classic to the average onlooker even if it's grey to match his vest.

Here's another classic route: Since the double-breasted models returned in the late 40s when the war ended (and are very popular now in non-wedding fashiony circles) you could also go with a double-breasted jacket and no vest, with a grey bowtie. 

http://www.menswearhouse.com/webapp/wcs/stores/servlet/ProductDisplay_10051_10002_10601_10128_-1_10002_Base_10651_?cm_vc=40168

Note that Mens Wearhouse gets it wrong here: you don't wear vests or cummerbunds with double-breasted tuxedo jackets. Also, if it had peak lapels, it would look a bit more formal/fancy. But the shawl is nice for a more relaxed formal look. Here's one in peak and done correctly with no vest.  You'd have to imagine the grey tie ;)

But the problem with double-breasted jackets is they can look dreadful if they aren't fitting correctly and most of us guys don't have the style/stones to wear them when the single-breasted look is more prevalent.

Good luck!

@Statutory Grape: Cummerbund probably makes him think Show Choir a bit too much. ;)

Is he going straight tie or bow tie? If straight, then don't kill yourself looking for a low cut vest.  I think bow ties look best with lower-cut vests, but straight ties look just fine with the higher cut modern vests.

@des_salazar: what is classic in your mind? A bow tie and vest is as classic as you could possibly get.  Now... maybe you're picturing this:

... which I agree is prom. But that's not the bow tie and vest that I'm talking about.

I'm talking about this look, which is completely different and transcends eras. It's essentially the same tuxedo as the 1940s tux pictured earlier in the thread except Chris Pine has his jacket buttoned and you can't see his waist-covering: