I found those flip kits too. Looks pretty simple.
After posting this, I found something that may be better for my situation.
Quick story...
Got a new truck and had to adjust the gooseneck. It adjusts by 2.5 inches at a time. Moving one hole only gave me 4.5 to 5 inches of tail gate clearance. Moved it one more and got 7.5 inches of clearance. Problem now the trailer is more nose high than I am willing to have.
Hopeful solution is, found that Reese makes a 1 inch extended collar drop in goose ball. Add that to the 7.5 inches then drop the gooseneck one hole. That "should" bring the nose of the trailer down by 1.5 inch and still leave me 6 inches of tail gate clearance.
Looking at the springs and axles, I think a flip would work but going to try the "easy" fix first.