I would also argue that they probably favored "greasy" (for lack of finding the right word) meat over lean one. Those who would live longer were more probably "richer" and thus more likely to eat more.

that's possible also, but they don't eat a lot of meat in Egypt. The rich could eat beef, but nobody else did.

no idea what socioeconomic class the mummies were from

They weren't pharaohs... no clue without more info