[Alamas]

I know the existence of two others, one with a MAC barrel of 1937, another one with an MF barrel from 1939 (may be the same you are talking about, serial 5XX). Like yours, three digit serials without prefix (on the barrel and on the stock, if I remember well). Emptied rear sight and bar for the sling instead of a swivel. I cannot remember anything precise about the german markings. Cannot remember who has sent the datas of these weapons to me, sorry if I cannot give the credit to who deserves.