Looking for someone knowledgeable on the M1903 or has one that is the same as mine. I have a few other vintage milsurps and I just picked up my first M1903 and I am starting my research. The only flaw so far is the elevation knob  on the ladder sight was broken off. I ordered a elevation slide and knob from Numrich and noticed that there are some differences from the original one on the gun. Below is a pic where I mounted the new slide on the ladder along with the old one so you can compare the two. The old one has some machining on it that the new one does not have. Now I am wondereing if there were different variations or possibly a previous owner did his own modification. Mine is a  1918 manufacture and the Numrich parts appear to be new/old stock parts.

The new part is the upper one, the original is the lower one.

The top one is the 1939 version.  The bottom one is the 1905 version.

Thank you very much SVT, thats what I was afraid of. I am now going to have to try and save the original one which may difficult. There is a miniature pin that holds the two slide halves together that has to be pushed out with a very small punch and the broken off shank of the old knob is still in the threaded hole, another difficult task to drill out something that small.