How many heads are on this zone?
What is the head spacing?
Do you have an open terminal on the controller and an extra wire?
Yes, you could move all the heads to the top of the slope. I'm thinking it may be best, even easier, to add a valve with one lateral along the top of the slope. One horizontal trench versus multiple perpendicular trenches. You will have to tap the mainline to add a valve.
This may have been a place where a fence was moved or removed? You can more than likely turn one of those nozzles off (or cap it) and never miss it.
Someone could have just installed the only nozzle they had there. The old way of installing irrigation was to pretend the sidewalk didn't exist and include it in the turf measurement and spray over it.
I read your other post too. It sounds like you have your work cut out for you. This may also have been a homeowner installed system. If not, the irrigation contractor who did this should never work on irrigation again.