Newbie here. I've been restoring and playing with vintage outboards for some time.....but I've decided to relive the days that I had hair and bought a really nicely restored Swift 'Big Dee' with a numbers matching running '59 Merc 55H1. Can anyone help me out decoding a Swift hull number to figure out age?

The number is UHD11206358114. It's on the transom 6"-8" below the top and pretty legible. I'm 99% sure that it's right.

I've got some (crummy cellphone) pics if that would help.

Any help or input would be greatly appreciated.

Thanks!

Jim