Allen, I think you're right to have a 3rd 772P car, although only 2 were built for the factory BMW team.
One is in UK, DBT racing, and one has appeared in Canada as a resto. project, but I think there are 2 cars with the same tag#. It would not be difficult to create a 772p as it is a narrow tub chassis car with std March parts fitted; it all depends on the tub front being flat or a slope and how steep!!
