Recently, I was required to check out a '71/'72 Fulvia 1600 HF for somebody.
One of the first things I noticed was that the chassis number stamped on the blue 'Lancia' VIN plate which was pop-riveted onto the top left (when viewed from the front) flat bulkhead top - whilst matching the chassis number reported on all of the associated paper documentation - most certainly didn't match the number clearly engraved into the engine bay rain-channel which runs along the top of the left-hand (nearside) wing.
Both numbers began with the same & correct 818.740 for a (LHD) HF version, but then showed different digits thereafter.
There are two possible explanations I've heard:
(i) This number in the rain-channel is only a (body) part number, while the actual chassis number is stamped onto the bodywork somewhere else; like along the rain channel which runs along at the back of the bonnet (something I didn't discover or look for)
....Or else....
(ii) Maybe this car is some sort of ringer?
!! (It has certainly spent some time in several other countries, abroad...)
The views & advice of the panel are kindly invited.