Honestly, I don't know. I didn't compare any Murphy Labs when I picked out my R0 because, to me, it's just a little too much aging. I do like the VOS aging, but even the light aged MLs have some "play wear" and finish checking. This is just a personal preference, though.
Based on what I've read online, I'm going to agree with
@Budda . I think it's the same materials (wood, definitely electronics) and the MLs just go through additional finishing to replicate natural aging.
You're right about the top grain not being visible on a GT, but the back grain is and the VOS RIs and MLs use one-piece backs while the production '57 Standard uses a two piece back. The grain is usually much more pronounced, too... for instance, check out the CS SGs vs the production SGs for a good example of the differences in the grain of the mahogany. Not sure if one sounds better than the other (I think two-piece backs have a better chance of having a sonic impact, but it's still small and probably not audible), but they definitely look better. With a purchase like that, for me when I bought my R0, looks mattered and ultimately became the deciding factor after I narrowed it down to the best three sounding.
About the wiring harnesses, RS does offer pre-wired harnesses, as does Throbak and several others. Pre-wired kits make it as easy as can be, with just the wiring that's passed through the channels in the body left to complete (pickups to volume pots (x2), volume pots to switch, and switch to output). Even if you don't complete the job yourself, it's still easier & faster (therefore cheaper) for a tech to do it. If/when you get to this stage, just make sure that the harness uses good parts.
Check out this thread from
@Andy Eagle - Tons of good info here!
https://forum.fractalaudio.com/threads/wiring-when-is-an-upgrade-an-upgrade.188990/