Gene:
The small alpha numeric code inside an oval or what is called the lever boss code for the 99's does show up on some post 1949 22's in addition to the 99's. Haven't seen enough to say all.
I think the OP is talking about the 4 character code used when Savage dropped the sn's on 22 and used this same type of code on the 99's. Of course the 99's had a SN but at some point they stopped putting it on the buttplate, buttstock and fore end and used the codes instead. It also shows up on the lower tang of the 99. It was a mix of letters, numbers and symbols but usually 4 of them IIRC.
I don't know if they really meant anything other than as an assist in assembly, maybe.
