Thanks! I have the M1123 and was looking for another one or two and they aren't selling nearly as many as they used to so I was wondering what other model is compatible. I noticed they are the same year models so that makes sense.
There really isn't a huge difference between any trucks within a generational type. Pretty much all A2 trucks are the same with minor changes or just how they are set up, same as all A1 trucks or A0 trucks are basically the same except for what's bolted onto them.
The 1097A2 and the 1123 are the "heavy variants" which means they are the ones that are supposed to be for hauling stuff, but that term also lost a bit of it's meaning because as far as I know all A2 series trucks are rated for 10,300 lbs. The 1097A1 was the heavy variant in the A1 series, and was 10,300 lbs when the rest of the series was rated 7700 lbs (or a little above that for some variants)
All the A2 series use the same drivetrain, halfshafts, whatnot, so as long as you stick with an A2 variant/third gen truck you'll have the same spare parts to share between them.
Once you get to the 4th gen and newer trucks, the ECV and REV trucks, there are a lot more changes, but most of the same exterior stuff will still bolt on the same way.