My three lug L61R is also in 338 Magnum. I bought mine in a Rod&Gun Club in Germany. The rifle was bought on a closeout in the GI club in the late 1960's. Some years later I had tried to get info on the rifle from the importer at the time-not Garcia. At that time F.I. found the numbers confusing. The suggestion at the time was that guns headed for the US had a different serial number range from those sold elsewhere.