Most just label the trail, since it ends at Top of the World. If books are the preferred method though, see FA Barnes Canyon Country Off Road Vehicle Trails Arches & LaSals Area, first published in 1978. Page 84 says that the rim itself is top of the world:
About 4-1/2 miles from the trail start, it reaches "Top of the World" The view here is outstanding. The long cliff-line above Fisher Valley extends to the east, while the verdant valley, its gigantic exposure of gypsum and the Onion Creek maze lie below the cliffs. The cliffs to the west blend into the soaring, dark red Fisher Towers.The photograph on page 85 also identifies the top as Top of the World.
The website below also list the point as Top of the World:
https://www.rr4w.com/trail-details.cfm?trailid=38"Top of the World" is a viewpoint on Waring Mesa. It has a spectacular view of Fisher Valley, Onion Creek, and the La Sal Mountains, but this view is only part of a variety of landscapes seen from this trail.....Pictures of your vehicle on the Top of the World overlook may not be part of your trail during Safari due to well being concerns for children and others on the trail.