Disassemble the fork leg.
Remove any rubber seal parts.
Get a socket or any round piece of metal/steel that will just fit inside the damaged bore put it vertically in a vise. Heat the outer edge with a propane torch or oxy/acetylene. Don't melt the metal just soften it so it can be worked back out to its right size. Work the aluminum out till you get a round bore and use a bigger socket each time you work it to a larger i.d. Use a mallet to tap on the leg when the leg is over the socket, you don't want to damage the outside of the slider.
As long as the oil seal bore is round and isn't leaking you should be able to fit a new dust seal and it should work.
If the piece cracks and breaks off you could put a new dust seal in place then use JB weld or a similar product to rebuild the broken lip. There is at least 3/4 of a good bore that will position the seal and allow you to rebuild the lip.
Seeing as you are putting gaiters on you don't need dust seals anyway, thats what gaiters are for. What part of SO.Cal are you? I live in Fallbrook which is 50 miles north of San Diego and could help you do it if you wanted to.I've got all the eqpt needed to do this Des.
