Keeler Spalding GM Pro Model?

[rholmes]

I won a larger lot of various items via an AH recently and with it came a few bats. I'll post one here and another in a separate post. The first is a Willie Keeler Spalding Gold Medal. It measures exactly 30.5" and weighs 37.5 ounces or just a tad heavier. By far the heaviest bat I've handled regarding length-to-weight ratio. The photos in the auction lot were non-existent and I didn't think there would be a chance in hell it wouldn't have the trademark stamps on the knob and/or barrel, but to my surprise...it doesn't seem to. No stamp on the knob for sure, and under magnification etc I can't detect one on the barrel end. It'd be nice to get any kind of thoughts on this being a non-retail or pro model (whatever wording you want to use)...

The larger question I have is, if it is pro model and I want to get it authenticated, are there pro/cons to using Mears over PSA or vice-versa? And with PSA, how do you begin to come up with a valuation for what you have if you don't know exactly what you have...which for some would be the reason for submission in the first place.

Any thoughts + opinions welcome!