Hi Phil.....welcome to TFF.
Your Colt Model 1877 "Thunderer" was made in 1888.
A couple of questions....does the double action still work? And what's the inside of the barrel look like?
Unfortunately, your friend's polishing job has hurt the value of this revolver.....and....there's the question if this gun left the factory with nickle plating or if it's an aftermarket job. The only way to find out is by obtaining a Colt Historical Archive Letter: http://www.coltsmfg.com/cmci/historical.asp
.......which will cost $100.
22WRF's value is about right. If it originally left the factory with nickle plating the value might be a bit higher. If it's an aftermarket plating job, I might value it (in it's present condition) a bit lower than 22WRF.....maybe about $600-700.