Hello!
For a "balanced" view!
Yes seen one before, handled one, touched one, spotted one on, witnessed it get crumpled in an accident and cried.
Spot weld marks would have been where someone put it on, then decided it was slightly out and took it off again to readjust and thus grinding marks. When putting these on you have to get it almost bang on else the windscreen doesnt sit straight trust me if youve done it you will know what i am saying a biut like when replacing a roof!! Despite the Mk 1's questionable body quality, design and exactness, the roof, windscreen and frame was somewhere that was a bit precise.
Cavity wax, well you would wouldnt you? Obviously was fitted to car in good hope and prepped then taken off for whatever reason.
The black primer that is on all NOS panels is for transportation and storage purpses only and should never be overpainted. True, honest! but bot a lot of peope dont realise and a lot of people swear blind it is the primer! Obviously thought of painting the underside.
Then again i could be completely incorrect.
Kind regards
SSF