I see all sorts of them on ebay and never having bought a body w/o them i have a couple questions. 1-how standardized are they...any chance of getting a set that won't fit a fender classic 60s body? 2-splined or smooth? I would think splined is the way to go, but there seem to be more smooth ones and both are available from fender so i'm wondering is there's something i might be missing. Thanks..