I used to have one, 1980 to be exact. I even remember the cost. $118.00 new.
If I recall the bow is adjustable for draw length, but common to that era, it is by moving the cables into another slot in the wheel. As such, I believe the bow would be marked for a given draw length so the cable would be in the middle slot. It can be moved up or down in 1" increments, but only 1" either way.
I don't have any idea where you'd get a measurement for it. Really, it's a fairly simple bow and if you have any experience at all with compounds then a manual shouldn't be needed.
If you Google it you might find more info, presumably on
www.archeryhistory.com