I won't go into details, but on a recent buying foray, I quoted out a bespoke .410 target shotgun.

Essentially,:
machine made gun at retail price
+ wood upgrade
+ outsourced hand chased laser engraving

End price, with 1 year wait, was 4X the price of the retail gun it was based on. No evidence that under the skin there was anything different than the retail model.

Who wants that?
It was 99% machine done, no special dimensions, and the engraving was 95% machine done. Where was the value added?

So, when I see an upgraded retail shotgun, I always ask the prospect, "What aspects of this bring additional value to you?"

Out there doing it best I can.