I just recently had cap fitment issues on my new Specialty Wheel 15x7's. All I had to do was about 3 minutes work to the hubcap mounting lugs with my Dremel. I used a polishing stone to just slightly increase the depth of the mounting lug behind the nubs. Very minor work, cap that would almost fall off now can't be removed by hand. Im glad I caught this prior to sandblasting and painting. Total fix time less than 10 minutes. I have original red circle caps.
I had no issues with cap fitment on the 15x6 Specialty Wheels I bought year prior.