itslow,
Good question! Each of them has more content than the proceeding version so it is not complete trade off (add the new model years' stuff and drop the oldest model years' stuff). There is some trade off as the catalogs are based on what Ford was still stocking as service parts.
The best bet for those interested in '32-'34 Fords are the '34 and '38 versions, both of which have been reproduced, at least in the past, and they show up reasonably priced from time to time on Amazon and ebay. The '34 version, for example, shows all of the '32-'34 door handles, inside and out. In the '38 version, none of the three types of '32 closed car inside door handles are shown, but all of the '32-'34 outside door handles are there. There are no door latches, window regulators, or window channels in the '34 version, but they are all or nearly all there for the '32-'38 models in the '38 version, including even some for Model As.