Just a FWIW heads-up, the basic Marinoni serial number code is known, and like some other mfrs, tells us the year of the decade produced, but not the decade:

Ser# xabc: "x" = year of the decade of production, ie: 8x, 9x; "abc" = sequence for the year. So 4123 would be the 123rd bike built in '74, '84, '94, '04 or '14. You need to deduce the decade by construction/decal/component evidence, original sales receipt, memory of original owner, etc. Keep in mind that repaints are not uncommon, you'll see earlier frames refinished with later decals---randyjawa's '74 has late-'80s decals/graphics.

Don't know whether current/modern frames are still using the same serial# format. Things can get complex when you're outsourcing some of your production, or if your production volume increases, and etc.