DRE makes both 1.25"LD(same size pipe as NRS. Inside diameter measurements for reference) and a 1.5"XD frames. NRS components(including the lopro) will work on the 1.25" frames, however, not on the 1.5" frames.
Is this going on the front or rear? With the front, I believe you would need to have an NRS floor to attach it to as the NRS and DRE lean bars attach differently, DRE's attach via fittings directly to the frame and not the floor like the NRS setup. If it's going on the rear I imagine you would just attach it to your back cross bar.