My m8 had a black xr2 like this years ago, check the engine number and the other vin tag against the v 5 I bet the vin tag matches but the engine number doesn't or isn't there

is there any markings on the windows?
Also check the date stamps on the plastics ashtray etc to see when they were made might be a good clue if the ringed car was actually built after the id car was registered

steve