In fact, the propellers marked 'A' in my shipment have the rounded edges for clockwise (and thus for M2 and M4, not M1 and M3).
Out of curiosity, and despite the rounded edge guidance, I tried the As on M1 and M3, and the non-As on M2 and M4, and the CF at full throttle did not take off (even slightly).
But the CF behaves as expected with the As on M2 and M4.
As stated in another post, it has been a great 1st week getting to know the CF (and beginning to explore the Python code), thanx again Bitcraze!

Cheers, Leland