Tractordata.com is the place to go. Here's link to "Farmall SM" data stuff: I'm not expert....but we're learning as we go also. "Boog" that posts here often is more knowledgable on the old IH stuff than I. Hopefully he or anyone else will chime in w/more info.

http://www.tractordata.com/farm-tractors/000/2/9/295-farmall-super-m.html

Looks like your SM was a late 1953 & built in Louisville KY, vs Rock Island, IL, near Moline. I'm not sure of the letters following the digits...not sure what if anything they mean. I think in that year nearly 1/3 of the SMs were built in LV. From what I've read/heard, IHC couldn't build them fast enough in RI, so they took their LV plant & diverted part of the production of the smaller tractors (Cubs, etc) & made more SMs to satisfy the demand. So far from what I can tell, there seems to be a little more value in the LV tractors vs RI tractors if restored 100% properly, but as far as "parade tractors", it doesn't make much difference. Your late '53 tractor will have the battery under the seat like a 400/450 etc and have the "pancake" style head lights vs the earlier "teardrop" lights.

Super Ms are very nice tractors, I hope you keep it & regardless of what others here will say, I'd restore it if it were mine, which I fully realize it isn't. Good luck! Maybe post photos if you can get some? Our tractor pictured below is also a "Louisville".