RugerSociety.com

Just saw a post on one of the gun blogs that said this person got his 437xxx range Single-Six lettered as an RSS5X, Ruger model 0212.
So Ruger has had their model number system probably since 1949 at least on an in-house basis. I think I saw an early RST4 lettered as Ruger model 0101 less than a year ago.
So it would be interesting if when somebody gets a letter on their Ruger, to post what Ruger model their gun comes back as, and maybe we can fill in all the blanks for model numbers for all the Old models, early DA's, or anything that came out of the factory prior to 1984 or so.
We can update this post when new model numbers are learned for those guns.
Chet15

I’m pretty sure none of my Ruger letters list this info but I’ll check them and report back if there’s info you can use.

None of my letters have the model number.
Bennett

Must be something you can get if you make a call over the phone.
Chet15

Based on my study of the No.1 model numbers, I think they went back retroactively assigning them. What year it was started, I don't know. Probably had something to do with the computerization and SKUs

Another point, if the autos were 010 and the single sixes were 020- the No.1's are 1301 for first 1A 243. Later, going to 013XX.
This fits the prefix numbering system, which starts in 1969!