I'm not 100% sure about anything unfortunately but they look exactly the same as the hallmarks on my necklace. I may go to Tiffany's today so we'll see if they refuse to clean it. Hopefully it's legit because I detest drama, lol.
If it matches yours, that's what is important. The Nordstrom thing is a huge red flag though. Why would you say that if it was real, or why even if it was fake?? So, so strange.