As posted by Mike Rogers:
All boats after 1972 have a Hull I.D. # usually found at the transom. It should be a 12 character code. Since your's is made by MFG the HIN will start with MFG then a 5 digit serial # followed by the month a year. It will show as either the numerical month folloed by the two digit year. For example December of 1973 would show as 1273. Or the other way is by M73E. The month designations are A for August, B for September, C for October, D for November, E for December. By now you should be able to figure out your boats age.
Also a sound piece of advice I can give you know when getting sails made for an old boat. If the sails on it are not original then have a sailmaker measure your boat to make sure none of the spars have been modified.