Crosman 112 without serial number

Just bought a Crosman 112 off the bay and it does not have a serial number. Wondered if anyone else has the 111 or 112 without a serial number?

My 115 and 116 both have serial numbers. I know the 112's were made between 1950 and 1954. I have seen pictures of other 112's that do have a serial number. Wonder when Crosman started putting serial numbers on the 112?
 
Mine is serial #285907, and I think it's some kind of limited edition model or something. 😉

112 Phantom.1606928738.jpg