First of all, I think you're referring to "Cinemascope" or "Panavision" (Anamorphic Widescreen) when you say "anamorphic ones, given that the aspect ratio is 2.35"
; I would assume you mean this as "Cinemascope" really has this as its aspect ratio (2.35:1) BUT this pertains to the way the film was shot
. Using same size 35mm film, using special anamorphic lens, "squeezing" the film then "unsqueezing" it thru a projector with a similar anamorphic lens...etc
However,in the Anamorphic DVD Process
(converting film to dvd), the original aspect ratio could be "2.35:1 or 1.85:1 or some other widescreen aspect ratio ; then the image is converted to an image with a 1.78:1 aspect ratio."
So, let's just make that clear and out of the way, ok ?
Back to your question, yes, Anamorphic transfers would have more resolution than non-anamorphic ones. Let's not say letterbox, since letterbox is just a "presentation" of widescreen films (films with aspect ratios of say , 1.66:1, 1.85:1, and 2.35:1 , bigger than the standard tv's aspect ratio of 1.33:1) hence the black bars.