Benchmade doesn't use Gun Kote. I believe you're thinking of BenchKote, also called BK1. It's their own coating, better than the old BT2, but it's still nowhere near DLC or even as good as titanium nitride (TiN) or boron oxide. I have a BK1 coated BM710HS, and to be honest, it's not all that impressive of a coating. Moderate cutting will mark it up pretty quickly, especially cardboard. Benchmade uses their coatings more to protect the knife from corrosion rather than protect it from scratching (probably only DLC is useful for that), and it does that well enough. I personally wouldn't bother with BK1 coating on a knife that didn't need it for rust protection (like my 710HS) since it mars so easily. I'd be especially wary of the coating on the handles, since anything else in your pocket (and possibly the pocket itself, if you wear denim jeans) will mark up the coating. Although I suppose the BK1 coating might be more scratch resistant than the bare titanium handles (titanium, although very strong, is relativly soft and easy to scratch).
I can't speak for the BK1 coated handles of the 635 you're looking at, but the BK1 on the blade of my 710HS doesn't seem particularily slick, at least no moreso than the bare beadblasted handles of the regular 635 would be.
I don't know what kind of washers the 635 uses, so I can't help you there. My two non-balisong Benchmade folders (710HS, 705-401) both have phosphor bronze washers though.
