The 91 mm small blade is not a “drop in”replacement for the 93 mm can opener. Not saying it couldn’t be made to fit, but by the time you drilled out the hole to accept the larger pin size, dialed in spacers and spring tension, etc., I just don’t think it would be worth the effort, even assuming you have the tools and skills to do it.
To the best of my knowledge, there have been three factory tools that have been offered in place if the can opener:
Electrician’s blade (as found on the electrician series of knives) - discontinued- Certainly a good option if you would rather have a second blade than a can opener, but it would probably make more sense to simply buy one of these knives and use it vs. buying one as a donor knife.
Pruner (hawkbill) blade (as found on Pruner/Rancher/Harvester/Swiss Army 7/etc.) - still current production AFAIK, but otherwise same story as the electrician’s blade.
Technician’s (small) screwdriver (as found on the Technician series) - These are discontinued and quite rare, but as suggested in a previous post, the can opener could be modded into a good approximation of this tool without too much trouble.
Some folks have modified the can opener into a package hook, by rounding out and sharpening the inside edge, so that’s another option.
Finally, if you haven’t already factored this in, many people (including me) find that the 93 mm inline awl is fantastic as a beater blade for pretty much any tasks that don’t require either a super clean and precise cut or a razor sharp blade. So, not quite a second knife blade, but pretty close in many applications.