Interesting. Today I was at the Carlisle swap meet and the guys at Performance Years shed some light on the subject. He had a picture of a PT code 67 TH400 and the tag is black, similar to 68 and up.
There was no standardized color of silkscreen for a wide range of years. All info I have notes that turbo400's were manufactured at GM Hydramatic. Some higher volume auto transmissions like Chevy Powerglides were also manufactured in Canada by Mckinnon Industries. My personal belief, is eventually at some model year, each year had several different colors of silkscreened tag, depending on the code of the Turbo 400. Going to take examining a LOT more original T400's to fill in the gaps.
-late '90's had a '67 PQ (real 400 HO, RA calibration) turbo 400, no sign of a silkscreen on the alum tag. Of course, it could have been really filthy and got the SOS pad treatment at the car wash. When I was in my early 20's did that several times.
-Have owned two '70 PQ's out of '70 TransAms, both, the silkscreen on the tag was PINK. Have had a lot of '67-72 short tail T400's, and that was only time I've ran across PINK as the color. Have a few '70 PR
code T400's out of 455 GP's, will ck them.
-The original PQ coded T400 out of my 455 HO GT-37 the screen print is turquoise, memory serves right. have a '71 PQ spare, as well, will dbl ck it as well.
-Hopefully looking at a '69 442 T400 this coming weekend. A fellow in MN had the '70 OW Coded 442 tags reproed about 15 years ago, that caused somewhat of an uproar at the time.
-Parts Place has been offering repro silkscreened T400 tags for last 2-3 years, several of the ones I'm knowledgeable with, the repro tags were silkscreened in the wrong color.