i need help in putting a date to a BSA AIRSPORTER MK1.near the trigger ther is two numbers as follows .(pat no 607.045 )and underneath that (G27748 ).COULD THIS BE THE DATE. ie 27 of the 7 th 1948. any help would be apreciated.this gun also has the BSA logo stamped in to the stock ,is this the norm on a mk1 .REGARDS MARK.