Yes, ask on a bmx forum.
If it's your friends bike, then that sounds better - or if you pick it up for 20 bucks, then that's cool. But, it truly is a question that is asked every other day after the purchase has been made.
If you don't own the bike and are just borrowing it - I wouldn't do anything on it as it isn't your bike. If you are thinking about buying it from your friend, find out exactly what bike it is. Find out 100% for sure what bike it is and how much your friend is asking and look at the condition of it and everything else.
Then, of course, you are doing the smart thing and checking the bike out and asking questions before you put your cash down on it.