Can only speak to one year...1957...but between me and smarter people here, we may be able to "range" it.
Mine was stamped. Probably at the frame factory before it was supplied to the line as mine is missing the the "3A" series code at the beginning. I assume that means the pillar tag was added after they decided on the 3100 series on the assembly line.
Could be wrong but Hope it helps.
Last edited by Fourbrads; 05/10/2012 2:47 PM.
