I'm pretty sure that they were made (possibly only for 3/4" scopes) but it might be a case of diving in all the parts bins at gun shows till you find one.
Could try Numrich Gun Parts or Western Gun Parts also.
A lot of people including me will cringe at the idea but it might be easiest to get someone to drill some new holes on the top for you if you really MUST put a scope on it.
Personally I would just enjoy it as the classic that it is and stick with the iron sights. They can be a lot more accurate than a lot of people give them credit for.