Quickly, as I should be working.
BB shell shows MC58, remember this is how Masi measures which confuses many, so the size stated is off.
The other numerics on the shell are consistent with late Carlsbad serial number stamping placement and numbers, might be 06 90 don't quote me on it. If correct I would place it shipped in the 4th quarter of 1976.
My view, late Carlsbad, repainted with added braze ons and ditched chrome.
If the number is 0690, then well past Mario's tenure.
I owned a late Carlsbad and think they are nice, This one will have IC lugs. I have trouble adapting my aesthetic to this bike's updated paint scheme.
John Jorgensen
Toiling in Torrance Ca USA