Thank you for your post and showing us a photo of your own SLI lamps.
It's good to hear you also have some "yellow-coloured" lamps date-stamped with 02, and they fire up a lilac colour. As I've got two of those yellow-coloured 02 ones, that means I should have at least two that fire up a lilac colour, and they all must date from February 1982. If they were from the only other possible dates - February 1974 or February 1966, they would fire up red.
The 'pink' one you have, date-stamped 22, is the one that I interpreted as having a turquoise colour. Having said that, I didn't even notice the lamps actually had different colours until I looked at a photo of them! Even though your 22-stamped bulb definitely looks pink in your photo, at the end of your bulb just under the 140W label there is a turquoise area, instead of the yellow colour of your other bulbs. Perhaps if I zoomed out on my photo, mine would look pink too!
In conclusion, I think your 22-stamped bulb and my 22-stamped bulb are from the same batch as they both have slightly turquoise ends. Feel free to fire that one up too if you have a spare moment, so you can tell us what colour that one fires up! If it fires up lilac, we'll know it's from October 1983. If it fires up red, it's from October 1967 or October 1975. My money's on October 1983.
The last bulb I have has 72 on it. If between us we are lucky enough to have a bulb that fires up in the old red colours, my money is on this one, because the more recent date of December 1987 is surely too late for SLI lamp production? I have a figure of 1986 in my head for when production ceased, but I may be wrong. The date before December 1987 would be December 1979, which was clearly before the gas change that happened "shortly after 1980" and gave the SLI bulbs their new, distinctive lilac start-up colours, according to the
LampTech site.
I guess the only way we'll definitely know is when we fire it up for the first time in the new year. I can't wait!