I was doing my annual cleanup of my dads guns this afternoon. He never shoots, and only has 3 long guns so it doesn't take long to wipe them down. Anywho, his little 22, that I shot many times when I was a kid, is a Glenfield model 60. I wanted to find out how old the gun is, but I couldn't find a serial number on it. I didn't take the stock off to look underneath the barrel, but there is no number on the barrel or receiver. What's up with that?