you could always change the keys if you want, and just leave the spacebar on the Leopold and the Filco respectively, anyways they both don't have lettering or anything on, so, there's no real reason to change them is it?
PS: if you get the leopold, and then the blank filco keycaps, then just use the leopold spacebar, in the end won't be much of a difference, and perhaps you get to sell the spacebar here.