A rather surprising question to see in a Forum, I suggest, because this has been talked about for many years.  Some years ago I was able to check directly with the Wikipedia source who owns JQ’s Log Book.

The answer in Wikipedia is 100% faithful to the log book entry by JQ himself.  Nothing further is added so the specific questions as to whether it was a two blade or three blade ‘prop’ just isn’t recorded in the Log Book. Nor is the Mark II serial number given.

So we must speculate for ever more about these two details, unless ……….?