The way that the Patterson-Gimlin film has evaded debunking for so many decades I could almost believe that you would be right and this proves nothing.

However, this guy here has seen the film and he is certain is is the same suit. And Bob Gimlin also appears in the documentary and finally admits it’s a hoax. As does multiple other people close to him: www.youtube.com/watch?v=WBuWLe1MC_A