GN 370A was an F7A built in June 1950 as GN 268A, and renumbered c.1960 to 370A. Similarly, 370B was originally 268B.
http://www.greatnorthernempire.net/index2.htm?GNEGNDieselRosters.htm
As such, the engines could have been used on any GN passenger or mail train in the 1960's.
The cars with the set are heavyweight cars repainted into the post-war streamlined Empire Builder scheme. GN did repaint a fair number of older heavyweight cars, but I think by 1960 it would have rare to see an entire GN train of heavyweight cars.
GN used smooth-side streamlined cars after WW2. Walthers made Empire Builder cars that are good representations of GN cars. If your layout doesn't have large enough curves (24" radius) for the Walthers cars, you can use Con-Cor's 72' 'shorty' smooth side cars instead. The Con-Cor cars are based on Chicago & NorthWestern "400" cars; interestingly enough, in the 1960's GN did buy some used C&NW cars and repaint them into GN colors.
Keep in mind you can buy passenger cars one at a time, you don't have to buy a full set. You can 'mix and match' too...say have a train with an Athearn heavyweight baggage and RPO cars followed by Con-Cor or Walthers coach, diner, sleeper, and observation cars.
So, I bought an athearn RTR GN F7 AB set used at a train show a bit ago. They are numbered 370. I know at least the a unit has a prototype down to the number, but I haven't been able to figure out what it pulled. I found this set on ebay:
https://www.ebay.com/itm/Athearn-Great-Northern-Empire-Builder-Locomotive-Passenger-Train-Set-C8-Cmplt/253518653818?epid=11017156907&hash=item3b06e3a97a:g:lHYAAOSwT8JatoCk
I was wondering if those are the right cars of if I should go after the smooth side ones.
I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.