Sometimes Doctor M. T. Graves is just a host of these stories, sometimes he's an active participant. This is kind of half-way between, as he arrives in the aftermath of a ghostly encounter that left his friend, a curator of ancient Roman art, hospitalized. The curator tells the story of his remarkable find of a stone statue of two lovers, and how it led to the lovers appearing to him as ghosts and telling about how they came to be cursed following Julius Caesar's murder. In a rather overly long epilogue to the ghost story, Graves investigates. I think that might just have been there to give Ditko/Boyette an excuse to render some more of the statues in the museum, which they do quite creatively.
Boyette seemed to pretty much follow Ditko's style, this story is pretty close to the other Ditko-inked ghost stories of the era, if it weren't signed I'm not sure I'd have had any reason to think it wasn't Ditko solo.
This story was reprinted in DR. GRAVES #75 .