To answer the OPs question. No they will not fit on a Rebel. The bumper filler panel between the headlights and bumper isn't as tall on the Rebel models as the rest of the 1500 Rams regardless of model.
This is due to the Rebel bumper being moved up higher than the rest of the 1500s. This makes finding aftermarket fender flares for the Rebel difficult at this moment. Currently there is only one model other than factory Rebel fenders flares that will fit and they are Rebel specific:
RealTruck ships the 2020 Ram Truck 1500 Bushwacker Pocket Style Fender Flares fast and free within the lower 48 United States. Take advantage of our product experts, image galleries, and legendary customer service to get the right part with no hassle.
www.bushwacker.com
If you try to mount any model fender flare other than a Rebel to a Rebel they would be approximately 1" to long on the front leading edge of the front fender flares.