When replacing the front wheel bearings on my modern KTM I found that the seals that go over the top of the bearings were 47x35x7. They are NAK brand,double lip and fit all Betor forks.Just great for my Bultaco's.
Pt no 0760 354771. Get them from Boltons KTM,free postage. $7.50 each.
Another way is to file 1mm off the back of the SKF ones,mostly there is nearly that much rubber on the underside of the seal.