It’s not Alps SKCM switches, but rather SKFS
http://deskthority.net/wiki/Alps_SKFR/SKFSThey’re not the same to disassemble, and I’m not sure whether it can be done without desoldering.
I’m not a huge fan of the switches, but if they’re scratchy, that means they’re in poor condition (the same thing can happen to any other type of 25-year-old switch). You can’t fairly judge the switches by the particular ones you have in front of you. If you want to give them a fair shake, find a closer to NIB keyboard. (Personally I wouldn’t bother though; there are much nicer switches out there.)
If you want to fix this board up, you could take everything apart, desolder all the switches, disassemble them, thoroughly clean the dust/dirt of of them, and possibly add some lubricant. It would be a huge pain in the ass though. Not worth the trouble IMO.