Ken,
As previously mentioned I originally thought that perhaps the 67 rear 5/8 rear sway bar ( GM Group Code 7.241; Part Number 3935776) might have been used with the mounting hardware modified to suite the 68 shock mount application or there was a 68 rear sway bar and hardware kit available over the counter. It doesn't seem that there were "other" rear sway bars available (over the counter) back in the day for the 68 - 69 camaro.
There is a kit for the 1967-1969 Camaro as listed in the 11-74 dated Chevrolet P&A catalog as identified above. The sway bar kit part numbers are the same as the F41 suspension option on a 1970 nova. My frame does not have the brackets mounted to accept the vertical stabilizer bars the run from the rear sway bar to the underside of the frame rail.
Does any one recognize this rear sway bar assembly on this 69 Camaro? Is it aftermarket? It looks vintage.