Actually, achievements do change timestamps according to your timezone so it's possible to verify solely via ingame. Something I tested out of curiosity.
Example: Get achievement at 8 PM Eastern. Change timezone of personal clock back an hour, the achievement will say 7 PM. This holds true for viewing other people's achievements as well, so it's possible to just have someone make a character and look at a person's achievements to verify.
Regardless though, thank you for keeping track of the progression.
yeah old trick, i always forget to pic with the clock ill try to do it this time lol, i always have to do like 10 diff pics to proof of different stuff, but yeah time stamp is the easiest way.