Oh it's real. The sprint package is a nice one to have, speaking from an OHCer 1bbl owners POV. I don't know the actual #'s but figure on a few thousand units, both conv & coupe. The OHC-6, both 1bbl and 4bbl were not as popular as the V-8 versions. Low sales #'s and the second gen 'bird killed off the Pontiac OHC in line six. The 2nd gen base 'bird had to use the Chevy in line six cylinder, with no 4bbl version. Snap it up since the prices for these OHC cars is a good bargain now.
