[Sav22]

From your description I think you have what was the standard rear sight on many models of Savage/Stevens rifles of the time yours is from - the No 19. The sight was designed to work well with a peep sight. The fold down feature alowed getting it down out of the line of sight when using the peep sight. The wheel in the center is a windage adjusment - the peep sight would also have windage and this allowed the sights to be lined up without having to drift the front sight.

 

[Sav22]

The rear sight would be folded down to use the peep and the peep would be removed to use the rear.

The front sight used a wire clip to loosely hold the inserts in place and then a slip on hood that really secured them.
http://www.gunpartscorp.com/ad/530320.htm
http://www.gunpartscorp.com/ad/557400.htm