My Beretta BM59... Help Identify By SN

[Skywalker]

Anyone knowledgable with the BM59 Beretta. I've read that some were made from welded receivers and others are modified Garands and even M14 parts as well. I have never gave it much thought but would be nice to properly identify what I have. Low serial number and PB stamped all over it except left side of receiver that says NY. Help me out if you have the knowledge of these guns and there is just to much on the web for me to know. I've had it for 12 years and my friend had it much longer. Some have the bipod and grenade launcher and even a winter trigger. Mine has none of those things. https://www.dropbox.com/sh/xmywtfcuw...vZre5p3wa?dl=0