[jeffschevelle]

So that proves the mixing in of old style and new style bulbs, since my 07B Baltimore has new style bulbs and Bill's 07D Baltimore has old style bulbs

As noted above one of my Ribbed low beams is 62 7 2. The other Ribbed low beam is ?? 7 16 (has no month or line stamp). See pic below. But it is presumably June 16, 1967, since car is 07B.

Both Ribbed high-beams are 61 7 5. So production line 1, June 5, 1967. See pics below.

I texted with Bill, and his clear triangle high-beams are 61 7 5, and 63 7 5, and his clear triangle low beams are 61 7 5, and 6? 7 5 (line # not legible).

So, all that suggests that:

- Production line 2 changed over to Ribbed on or before June 2, 1967.

- Production line 1 changed over to Ribbed on EXACTLY June 5, 1967 (since we have both versions produced on the same date.

- Production line 3 changed over to Ribbed on or after June 5, 1967.