Re: Savage 1895
The Savage 1895 had the viewing port in the top of the bolt so that you could visually verify firing pin condition. The Model 1899 had the tilting block indicator. This changed to the pin in the upper tang Jim K referes to in 1908 at some point per Murray's "The Ninety Nine".
Just changing out the bolt for an 1899 bolt is not a straight up swap. Different recoil shoulder design depending on the SN od the 1899. The bolt from a 1899 with a SN over 90,000 wouldn't work. Under that, maybe. Why ruin an 1895? Buy an 1899.