Attached is an exploded view of the forks. You will see that there is a shouldered steel bush on the splined shaft, then the inner link, and finally the leading link that carries the wheel. To get a good seal, the combined length of the bush, the inner link and the boss on the leading link should be about .005" longer than the dimension over the heads of the 2 bronze bushes in the fork leg. Any adjustment to the bushes or the faces of the leading link will adversely affect the operation of the seal. If the face of the link is badly scored, you can attach a steel shim to the face with 2 part epoxy glue (to regain a good sealing surface) - if you do this, fit a similar thickness shim onto the splined shaft between the inner link and leading link (to maintain the original clearances).
As you say, the seal is basically square in section, with one outer edge radiused to suit the housing. The operating face has a shallow groove to aid the sealing and also make the seal a little less rigid.
Regards,
Eddie.