Like anything with Ford production back then, it's probably possible that a very early '67 might have had an older '66 gray one left over used on it. Which might be where the info that '67's had them could have come from.
Or someone painted one 'cause they liked it and lots of people saw it.
There's a beautiful '76 on Craigslist right now (cheap too it looks to me from a distance anyway) that has '77 gas doors and the associated vertical side-marker lights.
Looks like a lot of effort was put into it (interior, paint and engine) but missing smog stuff so might be tough to register in CA. But if you live elsewhere, this might be a deal.
Would like to see it's VIN to see if it's really a '76 or a mis-labeled '77. Or just right at the cusp of the changeover.
Paul