Frogmckay- Welcome aboard. Glad to have you.
With rare exceptions, American gun companies used off the shelf sights when possible. If you can find a catalog picture of your carbine I might be able to ID it for you.
If it's a dovetail in the top of barrel, the dovetail is a standard size and can be bought. If it attaches by screws, the spacing will be .500" and also a 'standard sight'. You just need to figure out who made it and how tall it is.
I apologize for the pictures. the last picture was one i found on the internet. I included it to show the style of rear sight I was looking for. The pictures of the threaded barrel and the missing rear sight are mine.THat's a rough copy of a US M-1 Carbine. The top is grooved for a scope or that rear base. One screw is plenty to hold it on the dovetail.
The barrel is threaded for a suppressor and it's been used with one in place, by appearances.
Pretty sure that's an Erma Carbine. It says it was made in W. Germany so that means pre '94?
It's confusing to have two guns in the same thread!