Cool! I have a lifeline-era GRO-LUX lamp. It was NOS a few years ago but then it got put into use in one of my great-aunt's strip lights before I converted them to T8 this past summer. It has very light coloring on the ends. I also have a case of Sylvania GTE F20/WW lamps with the lifeline-era endcaps like this lamp. They were made in 1986. Not sure when they introduced the above etch style (was it around 1980?) but these endcaps were used as late as 1986 at least...

Nice save on that LifeLine Gro-Lux!
Really have no idea when they did this etch style, but my guess would be like you said around 1980.

Got a pair of these in a fixture at an estate sale (it was cheap & only got it for the lamps) had originally planned on using these for their intended purpose (either on houseplants or water-plants in a fishtank). Once I realized they were nice vintage-ish lamps, kinda hate to do that. I can say they won't be going in that wired-for-overdrive fixture I use for houseplants in my bedroom

I know they got rid of the cross-hatch etch in mid-'80 so I assume that's when this style of etch was introduced. For some reason (maybe it's just the lamps I personally own) these vintage Sylvanias don't seem as common/mass-produced as GE Mainlighters, etc. I have a Sears-brand "Soft Brite" (Lit next to a warm white it looks about the same IIRC) with the Sylvania Lifeline/GTE endcaps though that has hardly any use...may have been NOS before I had it in use for awhile too, in a Benchlite-ballasted shoplight...I should pull that lamp out and fire it up again, last I lit it was in 2013 or so and even then for a brief "It still works" test.

My favorite Sylvania etch was that crosshatch 'LifeLine' one
I don't see nearly as many Sylvania's in general as GE or Philips,

I liked the lifeline era "plus etch" best too for Sylvania etches (crosshatch is a series of intersecting lines so they name doesn't really accurately describe the etch). I see plenty of Sylvania lamps here. Altos actually seem to be the least common of the big three (fortunately). Places that use Altos make it very obvious too, with plenty of mercury starved and EOL lamps.

Around here Philips in general are rare, it's all GE and Sylvania.

Interesting...especially considering you see Philips *everywhere* here.

Yeah are GE and Sylvania relatively rare then?

GE's are fairly common, but I don't see Sylvania that often.

GEs are common in bigger stores here like WalMart, Target, etc but other stores tend to use Sylvania lamps. Altos don't seen quite as common as GEs or Sylvanias though. I think there's a fairly even mix though. This is just going by open fixtures too, though I can always tell when alto T8s are used because there's a lot of EOL and mercury starved lamps.

LOL that makes it really evident!