Hi there-new member-first post!
I am very ignorant about pre-war Lionel couplers. I have a very nice red Lionel 264e and 265T tender that I believe has a box coupler. I’ve read the Red Comet set had two #603 Pullman cars, and one #604 Observation car. My Greenburg book says these cars had latch couplers. I found a set of two #610 Pullmans and one #612 observation car which look like they have latch couplers. I do not have the passenger cars at hand to look at, only photos. To my untrained eye, it doesn’t look like the same thing. IIRC, I read somewhere that the latch couplers would work somewhat with the box couplers. My question is whether or not the coupler on the #610 will work with the coupler on my tender? I will try to provide photos of each.