I wouldn't buy anything from that seller. That's PCC motors other account and there has a lot of complaints about them around here. If I had a 50 I would be all over the pro 50 front end. Nothing against the fast ace stuff but I think those forks would be huge on a 50 unless you've got a big swingarm too.
Piranha Pro 50 Front End fits CRF 50 and Pit Bikes - Pit Bike Chassis Parts - Front Forks - Piranha Pro 50 Front End fits CRF 50 and Pit Bikes - TBolt USA, LLC