Hi, here's a comparison of the Lyman receiver sights for the Remington autoloading rifles and the centerfire Winchester self loading rifles.
The No. 41R is for the Remington model 8 and 81; notice the straighter curve of the sight's "arm".
The No. 41SL is for the Winchester models 1905, 1907, and 1910. Different location of the upper mounting hole- nearly underneath the vertical travel adjustment knob, and more rounded cover of the sight's "arm". Two different styles are apparent here- one (maybe later production) appears to share the similar sight base as the No. 41R, while the other (perhaps earlier) has a slightly different sight base.
Lyman No. 41SL on a Model 1905 rifle:
The location of receiver sight mounting holes on a Model 1907 rifle.
Or here's another model of receiver sight, (Lyman No. 38 or 21?) installed on a Winchester model 1905.
I have collected this information over the years from a variety of sources- I don't have copies of "Old Gun Sights & Rifle Scopes" or "Old gunsights : a collector's guide, 1850-1965" By Nick Stroebel - these are the best references I have come across about metallic sights. If anyone can add further information, please feel free to reply.
The sight in your last photo appears to be the Lyman No.38. The 38 was identical to the No.21, except that it was adjustable for windage and it had a flip-down aperture. Interestingly, neither the 21 nor the 38 sight were listed as being applicable to the Winchester Self-Loading series of rifles.
Lyman No.21 - patented June 25, 1895, and originally intended for the Winchester Model 1895. Later it was adapted for use on Winchester Models: 1886, 1892, 1894, 53, 55, 64, and 65; Marlin Models 1893 and 1895. Lyman No.38 - patented July 25, 1899. Originally adapted to the same models as the No.21, with the addition of the Remington Models 14 and 141.
Production for both ended in 1943, as well as for the No.41.