I have the front forks completely disassembled. The inner tube on both sides seems to have a buildup of heavy corrosion (picture attached). My question is if this is something that I should attempt to grind down? Part of me thinks that I should never grind on that tube to avoid it not fitting in the seal. Does this look so bad that I should get new tubes? What do you think?

I don't know your bike. But if the rusted part is concealed by the headlight ears, I might brass brush it on a wire wheel and leave it. If it's in an area over which the seal will pass, I'd be looking for new tubes, as you will be leaking again in no time.

Yeah... unfortunately this is a part that goes through the seal.

Use electrical tape to cover the rusted pitted area, then remove after the seal is in.