Here is a another fun thing you can do at the above link. Search the car number of the engine that you have (as well as non powered cars) and see if there are any pictures of the actual model. I have the greenbird R-26 set with the engine numbered 7840. Here is the actual photo of that car in use in 1970 - https://www.nycsubway.org/perl/show?3698
You'll see that when the R-26s remained in the original colors, no MTA signage was used even after 1965. You'll also see that MTH did a pretty good job modeling the actual cars that were in service and placing the correct number board on the cars.
I believe MTH made silver/blue and redbird R-26s as well. These would have a certain MTA logo depending on the date of the repaint. You can look up IRT (R12 to R36) cars at the below link. Just scroll down to the photo gallery search box and look up your car number - -
https://www.nycsubway.org/wiki/The_IRT_SMEE_Fleet_(R-12_--_R-36)
For some reason, its only linking part of the address and I can't get this whole link to work. Just copy the entire address here and paste it in your browser - https://www.nycsubway.org/wiki/The_IRT_SMEE_Fleet_(R-12_--_R-36)
For example, one of the cars in the blue/silver MTH R-26 is numbered 7776 (https://ogrforum.ogaugerr.com/.../mth-new-subway-sets). You can search for the car number and see it here pretty graffitied up in the early 1980s, with the appropriate MTA logo in use- https://www.nycsubway.org/perl/show?83716
