I was rooting around for options to expand the diameter of the lip just a bit.

Well it finally came to me I grabbed an extra 1 7/8 hitch ball and went to stand it in the dust cup. Damn it fell right in. Undaunted with my new idea I had a 2" by 1" shank ball I sat in in the cup and it rested on the lip I was trying to expand. I grasped the ball and cup and beat the dust cap flat onto my bench vice flat anvil portion and gave it 25 to 30 whacks and went to check the fit it was better but still not what I wanted so another 25-30 whacks and a recheck it was snug but still a hand pop on situation so one more time and the third try was good a gentle nudge in a couple spots with a hammer and an old flat blade screw driver and my dust cover fit like it should.