Here is my 2nd X359, I was lucky as I bought a bunch of Tilleys and never noticed it, and sorry no money shot boy as I need to make a new seal. So maybe one day The last photo is how i got it.
Just lucky that's all, timing is everything, I hope one day I can find a PL53 and a wall lamp they are on my list now but they are very hard to find.
If that's a new blow-lamp preheater seal you intend to make, best of luck with that! In the meantime, just use a standard preheating torch and let's see it running, eh...
November 1958 is, I think, the earliest date I've heard of so maybe X359 production lasted a year at least...
Sorry I should have had my glasses on, should be 11/59, also I have 8/59 & 6/60 I have asked to get the date changed.