Highly unlikely. Of course, caveated with never say never, swaps happen, etc. But the DFW is a planned A380 route and often runs at or near capacity, making a swap to a different aircraft less likely. It seems to have consistently been on an A380 for all of this year. There is still a small possibility of a last minute substitution (happen to me once on an IAD to LHR where a 777 was sent as a last minute replacement).

The bigger risk of the A380 is outright cancellation because an aircraft has gone tech. Though the DFW route seems less afflicted by that than other routes such as MIA or JNB.

I’m sure you’ll be fine sticking to your planned route via DFW.