Actually, they should (depending on size and thread pitch/TPI (mm)). The lens retainers on all scopes are ISO diametrical pitch thread. It's a matter of matching pitch to pitch and thread count to thread count and ID to OD.
I've found that Alumina covers can be a bit of an issue to install on any scope, especially if the scope has been in service (on hunts). The threads on the ocular and objective ends tend to get fouled with dirt and even dust can cause the Alumina's to be hard to thread in or not engage at all.
The cure is to use 'canned air' to blow out the threads (not your compressor, that air is too dirty). Then take a cotton swab and apply a tiny bit of silicone grease to the threads to the threads in the objective and ocular and carfefully thread the Alumina's in. Emphasis on carefully.
I have a couple customers that swear by Alumina covers so I get to install them on various scopes. My personal preference is Butler Creek, hand fitted to the optic. Besides, I consider it in poor taste to have a Leupy cover on another brand scope....
Best way to fit is disregard the size chart and choose by fit, not chart number.