Early 1968 GTS Fender Tag question...

Thanks for all the replies. I wanted to double check what the C4 could be. When I got the car it didn't have a sway bar installed but there was an 1-1/8" sway bar w/ OEM metal and rubber one piece sway bar bushings in trunk. I took the K-member assembly and sway bar to a shop to have the whole thing rebuilt front suspension and all. The one piece oem sway bar bushings disappeared but I was able to get a correct A-Body front sway bar from and forum member here in NC.