Thanks, Mike
Were those early rear sights unmarked?
As far as I know none were marked. For a 1901 gun you probably need one of these two versions of the No. 14 Rocky Mountain rear -
Not sure of the front sights, early catalog description says 'Rocky Mountain Knife Edge'. Most I see are either the same width top to bottom or have a round contour at the top. They came in different heights so you have to be careful not to get one to tall or to short.
The ones with the round top are real thin just below that and sometimes I see ones with the top broken off & just a knife edge left for sale.