We bought my son a used bike a few years back. you can tell its a quality bike. But here's the weird part... I have no idea what kind of bike it is.
It has GT Pro Series stickers on it... but the head tube has a Giant logo on it... it also has a Giant stamp on the frame gussets near the head tube. Its a red bike... and the paint looks excellent.. looks factory done.
Stickers pretty much mean nothing. Could be they bought parts or just got from thd bike shop. If its stamped then thats it. Heres link to various models Giant bikes BMX Museum Good luck with that