HFC Hop Up unit.

[Pivot]

I have an HFC Glock 17 (metal slide version) that I picked up on a whim. I've lent it out to teammates, and gave it to a friend. Said friend has since returned it to me citing lack of time to play. Now I've got a Glock that I really don't want or need (and a bill for a pistol that I'm picking up). When I took it to a local shop to consign it, I noticed that the slide was hanging up.

At first, I thought it was a piece of tape on the ejection port dust cover. After scraping of the tape and removing any remaining adhesive, the slide was still hanging up.

I took it apart and gave it a good oiling. Still hanging up.

I noticed that a guide on one side of the slide was cracked, and possibly burred, so I smoothed that out. Still hanging up.

My local gunsmith and teammate had a look and said that it was a piece had snapped off the hop up unit, and wasn't (missed the technical bits, but basically the barrel wasn't getting out of the way of the slide as a result).

Does this sound like a reasonable diagnosis? And if so, where the heck can I find an HFC hop up unit? Also broken feed lips on one mag? These parts seem impossible to find. Anything compatible with HFC that I can use instead?