I know I've created a topic similar to this but this one will have more detail.
Since I got my Ken Rad f4t5/cw, I've been trying to find when it was made, while I believe it was made in the 1950's, that's not very clear. The bulb has similar construction to some Westinghouse bulbs and a Sylvania bulb I have in my collection.
I'm not 100% sure which brand made this bulb because it is super similar to a Sylvania bulb I have.
I looked at Westinghouse datecodes on Lamptech however they didn't seem to match the datecode on the lamp so I looked at
Sylvania 1950's datecodes and it did produce a bit of a match. While I'm not sure if I'm looking at the etch and deciphering it correctly, the lamp was most likely made in 1957 because I read the 4 dots to the left of the USA on it and the lamp has an aluminum endcap (I think).
The month may be November or December because on the Ken and Rad there are two dots and a dash.
Does anyone have any other decipherings of the date code?