We can't answer for chrome on plastic as we have polished stainless steel. The ID nut size is larger than OD nuts with dimples on the ID nut cover for snug fit.
Not to hijak the thread as I am inquiring about stainless covers, but there is quite a price difference from online sites that claim to be stainless, from about $1 each to almost $5. How do you know what you are getting?The .89 cent ones I buy at Truck Pro rust quickly. I need to upgrade.David