Yup, can do this one the Wave screen before you start the fight. It's useful for a rough estimate of difficulty, as it can tell you how much extra HP and ATT/MAG the enemies have.
I've not done too many of the Frontier Dungeons yet, but for the base content, and most of the dungeons I have seen, the stat boost are often the same for all regular enemies, with Boss characters and the enemies accompanying the Bosses often getting an extra boost. This would mean they are not related to the talismans the characters are wearing, but I don't know if they ALSO receive further stats from the talismans they are wearing. It could possibly work like Relics, they only get the talisman stats once the fight begins.
Theoretically that could be tested using an attack that does %-based true damage?
UPDATE: It appears enemies in Madness/Insanity stages in dungeons do get their stats from max-levelled talismans, while those in Normal/Hard stages often receive a flat boost. Boss characters often receive an additional HP boost, but this is added directly to the white portion of their stats, not the +Blue part.