I've a RU77 Tanger in .338WM that has been modified by epoxy bedding, Mag-Na-Port, Decelerator Pad, trigger tweaked, rear scope base notched as a sight, front sight added ( came naked- and Ruger irons are way too obtrusive), stick on rubber cheek pad added to better fit my long neck. Needs refinishing, too. It's a tool which is accurate and effective.
It's a tool for my use. I'm unlikely to sell it any time soon, but if I do, the buyer will pay my price - or it won't be sold. I almost never haggle. I have never understood how effectively modifying a mass-produced gun to make it more usable reduces the value.... but there are a lot of Karens out there who think funny..
YMMV.
Now, a high end fancy piece, a work of art, or a custom piece- none of which I would personally buy - may be a hearse of another collar.