Is it possible to replace the iPad Air cellular model case?

I bought a used iPad Air 64 GB cellular model the other day. The shop I bought it from had repaired it, but didn't have a cellular model case so put it together with a wi-fi case they happened to have on hand.

It works great, and I probably will use it as a wi-fi model, but just in case it seems like it would be nice to replace the wi-fi case with a cellular model case so I can use a SIM card with it if I ever wanted to.

I can't seem to find such cases or guides on how to replace them anywhere though. Is this possible?

Thanks,

doug