I don't recall who, but someone on here recently sent theirs into Glock for refinishing, expecting to pay the $45, and got it back refinished at no charge.
Glock finishes are funny...they've used several different ones and some are more durable than others. My G39, which was built in 2004 IIRC, looks brand new. Glock put new night sights on it because the finish had worn off the sights, and now there's not a scratch, mark or sign of wear on it. Other than the serial number, you wouldn't know it wasn't fresh from the factory.
I don't know what they've been doing differently the past few years, but even the barrel hoods on my recent guns don't show the kind of wear the old ones did.
I want to refinish my glock 17, mine is USA fully made so it have MELONITE not TENIFER and it scrach very easily because i try to train every day in dry fire and my kydex holster scrach the slide in the edges. Here in guatemala the only finishes availables are the common BLUE and PARKERIZED DURACOAT wich you recommend me? or i can bring here some melonite to do it here in my country?