It is a 66-? Redeye. I can't tell weather or not it has the back clamp feet or the side clamp.
The back clamp feet were used up until 1923 and was the - 1 model. The -4s came introduced in 1923 when they went from the back clamp to the side clamp feet.
Yes it is a nice machine and if all the treadle parts are present it would be a very easy task to return it to it's treadle power.
Just remove the motor and light, and put a treadle belt on it.
Joe