I have a Glock 19 that's seen better days.  It's the Gen 3 (I think), the generation prior to the current.  It was dropped on gravel a year or so ago and the gravel left a silvery deposit on the slide which has since spread to an area with a silvery sheen (hope that makes sense).  Anyway I've had good luck with Gun Kote on rifles and am thinking of Gun Koting this slide.  I thought about sending slide to Smyrna to have Glock refinish it but I'm not crazy about being without the gun for a few weeks and I'm afraid they may do the slide in the new flatter finish which I don't like as much.  Few questions:

1)  What color to best match Glock slide? I'm trying to decide between Satin Black or a 50/50 mix of Satin and Flat.

2)  Does anyone have pics of holster wear on a Gun Koted Glock or other pistol?  I know it will wear more than original finish.

3)  Will Gun Koting my slide prevent me from having Glock refinish it at a later time?

4)  Anyone use 220grit Alum Oxide with Gun Kote?  I'm fresh out of 120 grit and so is Midway. Any other sources you guys recommend?  

Thanks in advance,

DOC