Just picked up my first Model 8, and I am trying to educate myself about this rare breed. I noticed that barrel sleeve is missing a rear sight, and is not even tapped for one. The rifle is set up with a Redfield peep sight, so there is no need for it, but I am still curious why it is missing. Did any of these come from the factory this way? My guess is that it was a replacement sleee
Any of you experts know what is going on here?

Thanks,
JB
Remington Model 8 - 30Rem
Vintage 1907