I had a 6904 in similar condition a couple of years back. I paid (a local gun dealer that also does light gunsmithing) about $50 bucks to have just the slide ceracoated in a satin black. Turned out great, and was wearing well.

Then somebody whipped out the cash when I priced it at what I thought was a "too high" price. I went and bought a stainless version (6906) and was able to purchase 6 more magazines (15 rounders) and some magazine adapters with the cash.

I won't be making that mistake again, but I'm really happy with the 6906. The ceracote seemed really durable against holster wear & such. I kinda miss that pistol.

Good luck whichever way you go, and please post up some "after" pictures. I can't seem to find mine on this phone. :-(