CALL- Contact Wilcox Corvette and they can assist with the Tru Flex bumper covers..
They really require new/different mounting strips to be installed and Wilcox has those also.They have also installed a bunch of them and know what all THAT entails...
IF your original urethane bumper covers are not damaged, they can be removed and subjected to heating using hot water or heat gun by a knowleable body man and they will 'recover' close to their original shape.
On more modern cars with the tupperware bumpers and body parts they do what is termed 'paintless' repairs for dints and such useing application of heat and gently pushing the dints out without damaging the paint..
Urethane has a 'memory' of sorts.
While you have them off, buy new mounting brackets with bolts to reinstall them..
It's challengeing to install them and get the fit good on edges and sides..but it can be done with patience and working with some heat while adjusting and then snugging the bumper covers up.The new bracket strips and hardware help immensely..Cost for front and rear on my 78 C3 was about 190.00 for the bumper cover bracket-supports which come in specific pieces and shapes to go right on.
I don't think ANY of the aftermarket nor the TRU flex( which are the best) are gonna be perfect fit without some 'mechanikin' tweaking and patient installation...
NOT like changing out a tail light lens..:(..Jim