Question about boat age & original serial number

[stevebrownell]

Thought I'd run a question up the mast and see if anyone on the forum has any ideas - I'm trying to get a sense of how old my 20 I/O is - the serial number on the original foil sticker that is affixed to the engine cover is "1201"

I thought the boat was circa 1972, but since the tank was above deck (inside console) I'm thinking it may be late 60's early 70's. I have a new HID#, due to the fact that we could not find one when I registered this boat, so this is more of a nice-to-know, versus need to know. Anyone know if there is a list around somewhere, or some information that can help triangulate on the boat/number/age question?

Thanks