I've had a 1300 sickle mower for about 6 years. I took all the sheet metal covers off to save because they were in excellent shape (looks almost brand new) and I don't really need them. It works fine without the covers. I had to lower the starboard side link on my 3 point to get the cutter bar to lay flat.
I don't use a hydraulic cylinder to raise and lower the bar. I just get off the tractor and do it by hand. It's pretty simple.
I don't have any PTO connection on the back of the mower for any other equipment. Only PTO shaft is from the tractor to the mower.
I've looked for an owners manual and haven't found one. I have the parts manual and it has helped. That manual doesn't show the PTO takeoff you mentioned.
This mower works great on the river bank behind my house.