First, look at the dial surface:
- It must be glossy. No gloss, no gilt.
Second, look at the lettering:
- Should be gold or silver. Originally, it was gold, but that could have bleached over time.
- And: the sure thing is that the letters are actually a hole in the laquer. You can of course only see that with a loupe, but that's the dead giveaway.
Third, the dial type and bottom inscription:
- if you have a chapter ring, it must be SWISS, meaning Radium. Watch out for your testicles...ok, just kidding.
- if not it must be SWISS T 25, meaning Tritium.
Fourth, the age of the watch:
- chapter dials are fifties to beginning of sixties (61 or so)
- non-chapter gilt dials are sixties, up to 66.
Fifth, the Tritium of 64-66 dials:
- it must glow strongly in green when put under light. Do not take that for SL. Lasts about 5-10 min max.
Ok, that's how I identify these dials. Probably not 100% right, and everybody pls feel free to correct me. We live to learn here
"A man with a watch knows what time it is. A man with two watches is never sure."