[Mr70]

I don't think it was a definite line in the sand when repeating that Jan.1st date.
Yes,orders taken after Jan.1st,1969 received headrests as mandatory.
But I'd guess some orders taken in late 1968,where the customer asked for the headrest delete/credit that were also scheduled for an after Jan.1st assembling date,were still built & honored with the delete/credit.
The one Chevelle I looked at w/o rests years ago had a 1st week of Jan. 69 assembly date.I don't know when Jim Ferrons Chevelle was built,but I'd guess it was early '69 too.
Here's a Chevrolet bulletin I have explaining the details of the headrest delete filler piece to the service dept.dated Oct. 1968.,with a subtle notice @ the end.