Yep, it exists, and, yep, it's at Dyer's.
And, no, in case you're wondering, it's not made in the same decades' old grease as the famous burgers.
The Deep-Fried P.B. & J. is part of the dessert menu, along with a deep-fried Twinkie and a deep-fried Suzie Q. I would describe it as tasting sort of like stuffed Beignet.
It will set you back $3.29. An extra .99 gets you a scoop of ice cream.