Hi,
the last dimension number is the width of the Seal: IDxODxW.
I's not so important as the ID and OD. So the 48x68x12 will fit in any case, the x14 maybe overshoot a little bit the seat.
The advantage of the narrower seal is, that you can position it at a slightly different position of the previous seal, if the shaft show signs of wear from it!
But in any case, fit it absolute perpendicular to the shaft.
46x70x14 doesn't fit!
Cheers Josef