1893 and 1894 stocks will be the same size, but all original Marlin stocks from the aearly years will have fit issues when swapped. Every Marlin back then was a custom fit gun, so when stocks were installed on a gun being built, they were fitted to the action. I've had beautiful like new stocks that I tried on numerous Marlins and found about half of those tried were very close, while the rest either wouldn't even go on, were high to the metal, or low to the metal.
It's a crap shoot if you don't have the stocks and gun in hand to trial fit. If you don't mind fitting a set of 90% inletted blanks, then contact Precision Gun Stocks, or Gunville. Both have replacement stocks that sell around $110-$125 a set.