Savman1, if you wander over to
www.savagela.org I think there is a scan of a factory letter in the pics section. It'll give you an idea of what it would say on a letter for your rifle.
Post-war 99RS's were surely sold, there's no way they'd run something like 10 years of catalogs and price lists with them but not have them for sale.
The problem is in identifying them.. Only difference between a post-war 99R and 99RS is a tang sight, and those could be easily added later - or removed. And I'm not sure that the model was written in the ledgers in the 50's, so even a factory letter may not prove that one is a 99RS.