1870's victorian mansion - great original faux graining on woodwork - planned to freshen with Valspar golden oak colored poly finish - have been warned not to as poly may not adhere. The golden oak Valspar poly is exactly the color I want but am afraid of problems. Have heard it both ways - some say no problem - others say don't. Any opinions appreciated.

What is the finish coat? Shellac? At a minimum you will have to sand the old finish and then apply the poly.

Valspar is an oil modified urethane which will not stick to anything unless you apply a chemical etching agent or you scratch the surface somehow. Sanding the existing finish with 220 sandpaper will scarify or scratch the surface enough so that the urethane sticks. One thing though, if there has been a wax of any kind applied, i.e. Murphys Oil Soap, Endust, etc. the urethane will not stick and will peel. You can strip with lacquer thinner and a rag first, then sand and you will probably be OK. I would test a small area and see how it looks in about a month if you have that kind of time.