I don't know if that is good advice to replace it? I know people are usually overjoyed to find real hardwood under their carpets or lino. The quality of the work back then was generally better as well and designed to last much longer.
Plaster walls versus drywall. The first thing I would do is get them as clean as possible. Get all the dirt ,wax etc off it. Does the wood seem dry or cracked?
If it is then there are products to help with that. I used raw linseed oil with a bit of turpentine to treat the raw wood of my shirasaya. That would probably be a very good choice as it does not change things that dramatically like a stain but helps treat and protect the wood as well as bring out some natural colour.
You could stain it but I would leave that as a last resort after linseed oil and
maybe a nice wax.