Whatever it is, the bottle to the left is ORANGE colored and has the same basic label, almost like Screwdriver and Cosmo mixers (did they have those in the '30s or would they just stock stuff from the '80s and hope you don't notice?). I did see a mixer that had that chrome style cap on top of the red one, but the label didn't match. The only bottle I've seen that resembles those two at all is Tanqueray, but it always has the red wax button in it. The label looks similar to Aviation Gin, but that bottle is different and it didn't come out until 2005 (ouch).
I even surfed through alcohol ads from the '30s and '80s while waiting for my microwave to be delivered. Nada. I even cropped the bottle and used an image based search plus vodka, gin, rum, brandy, liqueur and mixers.
Some slightly different photo grabs below (right one is later when Indie thinks he's shot for a moment, taken from a slightly different angle). You can almost read the label in the first one and you can see the left bottle has the exact same style label on it so it's probably a different 'flavor' of whatever it is. Maybe the 4K release when it comes out will be fully readable? The 2nd snap makes it clear that the left bottle contains an orange-like liquid compared to the red on the right and there's even more similar bottles to the right of that with the 3rd one over having the same black pentagon-like label with white lettering and metal screw caps. I think I see some Lucky Strike cigarettes sitting in front on the right. I'm not sure what that "Sp?d" pack is a bit over to the left with greenish lettering.
The bottle on the far left might be Gordon's Gin based on the label coloring (I buy it quite a bit as it's quite good for the price; I like it better than Tanqueray (made by the same company). Bombay Sapphire is slightly better than Gordons, IMO but costs almost twice as much and you can't really tell mixed with tonic water (Gin & Tonic) or sweet and sour mix and lemon juice (Tom Collins). I rarely drink gin straight so refined flavors matter little. Tanqueray, however has an herbal quality I can taste even in mixed drinks that I'm not crazy about.
