Ulrik,
Welcome to the board! I have not seen anything definitive on the difference between a Beretta S or SO guns. Look at the frame marking on your sons 1953 gun. Is it marked S-2 or SO-2?
I have the old pdf file from 2004, but I don't know how to post it to the site. The information isn't all correct in the post. From the late '30s to the '90s, the main difference in the guns is Beretta upgrading the lock design. A gun from 1940 and 1953 should have the 7-pin design.
Also, you may know Beretta made different models of the S or SO:
S1
S2
S3
S3 EL (in the states, Garcia imported them, in the late '60s and early '70s, as SO4s)
S3 EELL (in the states, Garcia imported them,in the late '60s and early '70s, as SO5s)
SO4 (replaced by the SO5 from Beretta in the late '80s)
SO6 (replaced the S3, S3EL, S3EELL in the late '80s)
SO9
SO10
Ken
Last edited by KDGJ; 03/21/17 11:41 AM.
