Blake,
I think if you have covered all your clean, bright blasted metal with a 2K primer, then you are, as they say, golden!
You can Bondo and sand until the cows come home as long as you don't break through that primer coat to metal again. If you do, you will have to seal it.
When you are all done with your Bondo and other fillers, you will coat it all again with 2K again (I think). This will seal the porous body filler and allow all top coats to gloss and dry evenly.
All you care about is keeping any bare metal sealed from the atmosphere.
Stuart
