As long as you can carefully cut the underslung coupler off, there should not be any problems. This will not be easy but doable. Don't cut into frame or you will have extra work. New couple must be of the size, angle and strength. The angle of the A frame could be the one thing to stop you. Should be standard A frame angle but never know for sure unless you double check.
Hire a pro to weld it, I am a certified welder, you don't know how many times I have heard "Oh yeah I can weld" and they can't. We as welders are tested quite often just for that reason. I recommend having everything done by a pro.
You will have to remove tongue jack temporarily. There also might be a issue with the existing jack mounting plate, but doubt it. Just grind welds flush with plate first. At the worst it will have to be cut off too. Keep in mind the existing jack hole and the one on the new couple probably won't line up with each other easy enough to deal with if you are going this far already.
2016 Ford F250 XLT 4X4 6.2L
2015 Rockwood Signature Ultralite 8329SS
Nights camping in 2016: 19 nights
Miles traveled in 2016: 2,575