Buying a 6536 is a minefield! You should ask for much better pictures, even macros of the dial to seek opinions about the lume. It’s a Swiss only dial, so it should be radium, also ask for a video of how it reacts to uv light. It should charge and glow but fade very quickly after exposure.
I’m no expert but I’ve been in that situation waiting for more experts to say what they think quite some times 😁
Also I would expect the original hands to reach the chapter ring which it does not here...And wonder why the insert is so clean while the dial/hands show a lot of damage/patina (not saying there is a problem with it, I don’t know enough but it might show it’s not original to the watch). Lugs also look thin from here but maybe that’s just the pictures...