I actually posted this in one of the threads talking about glocks but on the website of my local gun store they talk of a glock refurbishing service that glock does.
They claim that glock will refinish the slide, spruce up the frame, replace any parts that may be worn, install new factory sights and upgrade any parts so that they meet current specs for a very reasonable fee + shipping. Give them a call for the current fee for this service. They also say you must specifically note you want the slide refinished when sending it in. Anyone actually ever done this and know the price? I know my pops was thinking about sending his glock in to have this done.
link is here http://fsguns.com/glocks.html
at the bottom of the page