Thought the same myself. When I saw the engine I thought it was standard Rapier with a Holbay rocker cover. Maybe it is? Don't know why you would retro fit twin strombergs to a Holbay (interim measure if your Webbers were playing up?).
Surely this car is know to the club?
Just checked to post 'H120 and counting' and its not on the 'known' list of genuine H120's.
But I guess the vendor isn't actually saying it is a H120.