Ah-Hah! So, if you are not under that constraint, you can do with it as you darned well please. You can add a rear sight in any manner that you want. Depending on your eyes, you may want to add a peep sight. That will require a bit of looking to find one that will work on your gun. I have heard of folks who have made a peep sight from a bolt and then drilled and tapped a hole in the tang of their rifle. That requires flattening the head of a bolt, grinding the flattened head into a nice, round, disk and drilling a tiny hole in it. The elevation is adjusted by screwing it in and out. Because of this, it is best to use a fine thread bolt. Unfortunately, such peep sights are not adjustable for windage. Note that I didn't say it was a perfect idea but it works for some people. If you want a peep sight that is fully adjustable, you will have to find one that can be mounted on your gun and that may require the services of a gunsmith.
You can add a traditional open sight if you have enough metal in the rear of your barrel by either dove tailing it in or having a gunsmith drill and tap for screws. Before adding a rear sight, you need to place the sight on top of your barrel, sight down the barrel as if aiming your rifle and then have a friend move the rear sight forward and backward until you get the best sight picture. As we age, our sight changes and younger eyes can see better with the rear sight closer to the back while older eyes will benefit from moving it forward on the barrel. Find where it works best for your eyes, mark the spot with a piece of tape and then tell the gunsmith to put the sight right there.
I keep referring to a gunsdmith simply because unless you are experienced in cutting dovetails in your gun barrel or know exactly what you are doing if you drill and tap for screws, you can quickly ruin a good barrel and that will cost you somewhere around $200 for a new barrel. The same if you want to solder your rear sight on. That is not so hard to do and you are less likely to ruin a barrel, especially if you use a low temp solder.
If you have enough "meat" in your barrel for a dovetail, that is the way to go because you can eaily adjust for windage by just drifting your sight in the dovetail.
So, there you go. :hatsoff: