Been following this for about 15 years Just don't think the subject has come up on this forum since it opened
Yes there was a period of time at Dearborn that some of the paint inspectors were reassigned the 64 style of stamps. May have been an issue over the supply of stickers by the outside supplier or some other reason. Two different inspectors have been documented
What is interesting is that the other (non-paint) inspectors continued to use the sticker method in most examples.
Currently documented between March - June 68 at Dearborn
Never heard nor documented this being the practice on 67' s maybe a comment from someone that didn't check if they were lookign at a 67 or a 68