Using universal clear and miseed a spot.
Actually the entire under side of a drip rail
And a smaller portion on a door.
Its 12 hours since the last coat.
Can I just clear over this nason base
Or scuff and clear
Only way I would do it would be to mask it off, done so in a way that you don't leave hard edges. Don't just spray the area as the clear will not melt in to the existing clear. If you have too, mask off, prep and spray the entire panel. As for sanding, 1000 is way too fine. 800 would be my choice. 600 will work fine as well. Don't go crazy sanding it, just flatten and remove the texture. Just to avoid any issues give it 24 hours before you attempt the repair just to be on the safe side.
Should have added if you are able to just do the area where you missed with clear, don't sand it if there is little to no clear. If you have a grey scotch brite that would be the most I would do there. Very lightly. Any area that has clear on it you'd want to sand but in that area where there is none or just light clear overspray, just scuff it very lightly. And waiting 24 hours minimum would be smart.