Well, here we are at the other end of the spectrum. Last month someone asked me to help identify their Remington 1894 and it turned out to be the rare-est that is known. A Model 1894 EE grade 16 gauge, POW grip and 2 barrel set. One of only 39 known EE grades. One of 4 16 gauges in EE grade. One of 2 two barrel sets in EE grade. Nothing else like it.
This is a well used and not well cared for Model 1894 A grade made in 1900. As has been pointed out, Damascus barrels. In assessing an old gun like this, the first and main thing to consider is the state of the barrels. Everything else can be fixed, if one wanted to. Are the barrels original or have the chokes been changed, the chambers lengthened, the bores honed so many times the walls have become dangerously thin and are the bores pitted.
This is your grampa's gun and often that can mean sentimental value for you that is different than with an ordinary gun. So I'll be realistic here with what likely is required to get the gun looking and working great and ready for another 100 years.
Assuming the bores are good and the chambers haven't been lengthened and barrel walls haven't been honed too much here's what you might be into:
Fix the rib. I haven't had to do this on a gun yet but it is really not going to be cheap. My guess to remove, repair and relay the rib, at least $400.
Re blacken the Damascus. $500-$600 These barrels would have left the factory with Black and White Damascus barrels.
Redo the stock $500 Would include repairing the cracks properly...yes there are cracks, removing the accumulated oil that is soaked into the head of the stock and is weakening it, glass bedding the stock to create a proper new receiver to stock fit as well as strengthen the wood
Strip and clean the action $125.
Put it back on face $250
Refinish and CCH the receiver and bits. $300
All that is also assuming the mechanicals work properly, hammers #### and fire, safety works. Any problems there and it's just more money.
Do all I've listed and you will have a stunning new (old) gun that your grandchild can inherit and enjoy. But it all starts with the barrels.
Oh and after you've dropped the $2K into it, you won't see a dime over $1000 if you have to sell it.
To specifically answer your question about value....I like and own several Remingtons. I'm always looking at what comes on the market. With the busted rib, I would think long and hard before I would give you $100 for it. But that's just me.