I just found we have a job with one of these old dover rotary units (1957) and one of the more seasoned guys in our company said it's an early GAL product and not sure of availability. The clutch used is stationary and doesn't have a retracting arm so you may not be able to use a stacked roller set up with both rollers on it. You could probably use a dover /tk clutch and add ramps to pick the retracting bar
