VIN number help needed

HELP NEEDED WITH VIN NUMBER



We have a Shasta trailer that we are rebuilding from the frame up. The VIN tag has been missing, but when we began wire brushing the frame this weekend, my husband discovered what we think is the VIN # stamped into the frame, below where the missing plate should be. This is the number - A221 006467
.  What does the letter and the number mean?


Can anyone assist us in decoding this?


We have a title and it says it is a 1977 / advertised as 1976, but since the VIN plate was missing and number unknown, now I am wondering if this title was not the original and may have  been applied for with a bill of sale and not the correct information.


Thanks for any assistance!