Drew Cutter wrote:

I don't know what the floor is below. Does squeak and floor nail popping
out. If the wood on the house is any indication of what type of job they
did 55 years ago ( new siding put on ). Then the stair need to be looked
at. The Realtor coming out Monday.

What's covering it up now or do you mean you just can't recognize wood
types?

If you're just trying to "fix-up" to sell, probably all that's needed/is
economically justified is to reset any loose nails, maybe shim a step or
two if there's access underneath, and refinish the existing treads...