I have a fretless unlined G&L neck on an ASAT body, it looks similar wood wise and the same pilot holes, the filled tiny machine holes, same tuners. Mine is ebony, that looks like ebony to me, the craftsmanship is great on G&L usa necks. The ebony is hard as hell, no dead or over buzzy spots, I never did anything to my bass except play the hell out of it and it has zero problems The Mojave desert where my bass lives has temperature changes of up to 115 and back down to freezing and it takes it toll on micro adjusted necks. No problems with those necks. Mine is a three bolt which indicates an older neck. Ask to look at the neck plate. Don't take your cord out with the preamp off you can fry the pre amp chip.

. I did install dual coil tapping on my M2500 (serial/outer single coil/parallel, separately for each PU - see picture below), but there was no passive option. Having two individual switches added subtle differences to the tone capabilities. I (mistakenly) sold the bass more than a year ago, the playability of that #10 neck was a dream (for a fiver).