Confusing Serial Number on 2203 vertical input

[Slick George]

Hi, all you knowledgeable people. I ve had a vertical input 2203 since 1994. The serial number confuses me as it says S 01132. I couldn't find any source that could tell what year it was made and it seems like maybe somebody didn't stamp this right. Everything else points at a pre-84 2203, sticker says 2203, handwritten signatures on it. I don't want to sell it, I'll probably play it until it/me dies. I'm just curious about me ol' noisemaker. Appreciate your comments!
Cheers!

 

[LPMarshall hack]

http://www.voodooamps.com/home/MarshallDateCodes


84...nice amp!

 

[Slick George]

Thanks! Will post pics as soon I get back to rehearsal room.

 

[Slick George]

Maybe one of the last with vertical inputs as Marshall had changed to horizontal by 84.