For the sake of more meaningless chat
the ad says W6, so already a typo, for an option not available in '77 but may have been added to some extent, as mentioned. W72 for 1977 wasn't a terribly exciting affair, compared to the beefier block and slight extra power of a year later. Not sure what the HO reference is, could be someone like H-O Specialties, or just the owner assuming 'Bandit Editions' featured HO engines.
You're missing the big value-adders though, the rare factory tinted headlight (and grille) covers, to match the shades of the driver! They haven't aged as well as other retro things like big tyres and rear louvres.
And it wasn't always indoors...!