Agreed. It’s not like we ever see those two elsewhere in the saga. Even if we did, it would likely just be in comics.
I’d say keep what makes the most sense in the context of the film itself, which is Evazan’s arm with a blaster.
Yeah there’s a canonical story where Dr. Evazan is trying to fix Ponda’s arm with some janky prosthetics.
Besides that… it’s true to the original film.