I have spent over half an hour, about 10 minutes yesterday and 15-20 minutes this morning looking over this weatherstrip and the only markings i find are an "R" in the right lower corner and an "L" in the left lower corner.
Unless I somehow missed the markings are on a face edge inside the grooves for the glass or the pinchweld, which I spent a great deal of time examining also yet did not find a marking, I have yet to be convinced it is genuine.
If somebody has other ideas where to look, I would rather approve this part as genuine, than to disprove it.
Too bad we need to be suspicious.