Correct.
A “-1” would be one piece for: retainers, springs, spring cups, shims, pushrods, valves, rockers, rocker studs, lifters, and a pair of locks, etc.
Whatever plan the OP has regarding Comp “766” retainers, I’d say since they don’t seem to exist(at least not any longer), he might want to consider an alternative that’s actually available.
I’d just look at the spring dimensions and valve stem diameter/lock groove they need to fit and come at it from that angle.