About a month ago, I talked to an attack pilot who flew Corsairs in WWII and Korea. He said that their preferred method of divebombing was to drop gear, dive vertically (even up to terminal velocity in that configuration), drop bombs or sometimes one bomb from among many if they were going after multiple targets, then pull up hard. It didn't sound like he was concerned about any g limits on pullout, even in the case of Korea where the Corsair was loaded up sometimes with 4000 lbs of bombs and pulling out of the divebombing attack with many bombs still undropped.
This is anecdotal, in that I don't know how many g's he was pulling on pullout, how many bombs he'd have on pullout, etc.
Some planes did have g limits when loaded, where if you pulled too many g's with too much load, the wings would fail. The P-51's wings might not be sturdy enough for large g's with load. It's possible some had attach points that would fail. But then there are others (like the Hellcat) that routinely got into dogfights with fuel tanks attached, P-38's that (inintentionally or because they were hung) got into dogfights with 500 lb bombs attached, and the above story about Corsairs.
Given that, lacking any hard evidence to the contrary, I'd go with most fighters being able to AH's blackout g's with bombs attached.
