I think if you and your partner were both developing a route, cleaning it, bolting it, and you flipped a coin / took turns to see who would get the first redpoint (and the other follows with a redpoint), then you both deserve credit.
What kind of coin, specifically?
Do you have to call it in the air, or before the flip is initiated? Does it have to land on the ground, or do you have to do the hand catch, arm slap deal? Is it two out of three, or only one flip? How do you decide on who gets to be the flipper and who is the flippee? Who supplies the coin? Is there an independent third party to verify the results?
These are important considerations to have clarified before the big moment arrives.