Hello cousin 155 owner; thought I'd chime in here as you haven't had a reply yet.
From my limited knowledge, yes the 16 is a Lampredi, both 16v & 20v have belts.
The 16v belts are indeed fragile and need to be changed more often than the 20v. Replacement 16v engines are VERY THIN on the ground, whereas 20s are two a penny relatively.
FWIW the belts don't so much break on the 20v: the aux belt is more liable to go or fall off and takes the cambelt with it. There are one or two aftermarket solutions to help discourage this though.
Don't know if this is any help at all, but welcome anyway