I don't dismiss it out of hand. If it were mine, I would want independent confirmation and not from an image. If you like it, want it, to be certain, send it to someone you trust to give you an honest answer. Photos can be deceiving. Did you buy it from HA.com? Maybe they're not independent enough.
Posting the weight in grams and the diameter in MM is helpful in detecting fakes as well. The second coin looks funny to me. The flan is very large and the beaded border looks odd. Can you post a picture of the edge and reverse. If you want ancients from trusted sources, try vcoins.com. John
Heritage outsources most of their ancients authentication to NGC so I'd take their opinion with a grain of salt because at the end of the day they don't even seem to rely on it too much. On top of that, major dealers and whatnot do make mistakes, especially when only working with photos.
I'm not really familiar with provincial tets or LRBs, but I think the first one is probably bad and the second probably good. On the second one, the portrait, devices, and letters all look pretty good, but I don't know enough to say whether the border looks funny or not. I will say it's unusual for them to be struck on such large flans though.
I see, larger flan, thats exactly what i was concerned about as well as coin looking too "perfect" for my eye, but I might be wrong, not an expert,
I don't know how rare your particular coin is, but you can get some very nice bronzes for not a lot of money. The fact it looks so good doesn't faze me a bit.
I can't make out the mint is biggest. But the lettering isn't jivin with me. I have 3 Diocletian tets but from Alexandria & Antioch. I'm trying to compare them. Obviously the Alexandrian tets are thicker. To me your coin seems awfully thin even against an Antioch. The lettering bothers me the most. I'm still learning ancients so my knowledge isn't golden.
I beleive so & upside down in your pic. If I stand on my head it looks like AOD mint mark. That can't be right. Understand I use posts like yours to learn from also. I can tell almost anything on modern coins but only a 6 month newbie to ancients.