YOu might want to see if he has all the parts that he took off that.

He's basically got it as a 10 speed bike. YOur BF is likely going to want it as either a double or triple on the front crankset. So in addition to the shifters you're talking about buying, the flat bar - if you don't get the parts he took off, you're talking about a new front derailleur and a new crankset.

At that point, it's not a bargain for $500, given that you're gonna be putting a few hundred in parts & labor.