Replacement stock suitability odds...
 

I own a gun made @ 116,000 guns and 26 years apart from a stock that is in good shape. That far apart, is there much chance the stock can be fit to the gun without too much work? I think the answer is "not likely", but I don't know the reason why? Is the newer stock likely to be too big or too small, or is that not really how it works?

I think "fit" will depend upon how particular you are

You never know till you try. It could work well, it could work well with some work, or of could not work at all.

Apart from proximity of manufacturing dates, the drop of the stocks as compared to one another is the other major variable.

Assuming they are the same frame size, fit without some work will also depend which is older, stock or gun. The hammer projection is further back on older guns, but I'm not sure when the change was made. A 216,xxx stock would need to have some wood relieved from the head, to fit a 100,xxx gun, but not vice versa.