Texas Hold 'em would indeed have been unusual; Albert A. Ostrow's The Complete Card Player from 1949 has 16 pages on Draw Poker Games, 12 pages on Stud Poker Games and 8 pages on Other Poker Games. There's no Texas Hold 'em (the only Texas is "Texas Tech" as another name for "Double-Barreled Shotgun"), though "Cincinnati" (also known as "Lame Brains"), "Round the World" and "The Cross Widow" are community card games mentioned briefly in the "Other" section.

Magician and gambling expert John Scarne consulted for Yank magazine on a series of articles in 1943 illustrating the dangers of crooked card players: "[It's in the cards] (http://www.unz.org/Pub/Yank-1943apr09-00008)" concentrates on the shuffle, cut and deal, "[It's in the cards (part 2)] (http://www.unz.org/Pub/Yank-1943jun04-00008)" illustrates sign language used by collaborating players. Specific games and variants generally aren't listed but there are scenarios that correspond to five card draw, and there's a note to particularly watch out for players holding cards in high spades. "[Marked Cards] (http://www.unz.org/Pub/Yank-1943jul23-00008)" notes that card marking is most profitable in stud poker, blackjack and red dog.

I'm afraid I'm not sure of the relative popularity of particular variants, though poker is frequently mentioned in memoirs I can't recall any that go into detail. Ostrow says in the introduction to the poker section of The Complete Card Player: "The lively process of ferment and change in poker today can probably be attributed in great part to the fact that more women are playing the game, and that returning servicemen are bringing back exciting versions of their own."