I don't know why exactly vintage razors are not viewed as antiques (the ones which are) and treated as such. With antique restoration every effort is made to remain true to the original.
If you are just becoming interested in straight razors, I wonder why you are already thinking of resale?
In vintage razors wood scales seem to be found only in farmer rescaled razors. It is the chemical finishes that have made wood more practical in a wet environment, like super glue.
If you have off gassing celluloid, you could use acrylic to replace the scales. If the scales have a crazy color or sparkles or whatever, you can probably find something parallel in modern materials.
With a custom razor, any choice of scale material is cool.
Finally, if you replace scales, keep anything that is not destroyed by unpinning.