Is there a G15 register of date of manufacture?

[appleyard]

Apologies if this is not the right forum for this query, but does anybody know if there is a register that can be accessed of when a particular car/chassis number was manufactured? I have recently bought a G15S which was first registered on 6/1/1972. I want to find out if I can get confirmation that it was a car that was manufactured in 1971. This could help in identifying which MSA class it should be entered in for competition purposes. Thanks in anticipation.