Yeah I had one that had snapped. I was stripping the engine down to a long block at the time so ended up drilling the remainder of the fuel pump intermediate flange (to give it its proper name!) out, working up the drill bits in size order and then flushing it through with oil.
I guess the problem with a built engine is as soon as you start it up it'll push the swarf through the oil gallys and risk clogging them.
I guess the option that avoids dismantling the engine would be drain the oil, remove the sump plate and strainer, flush the hole that the flange sits in with a flushing oil, refit sump plate, fill engine with flushing oil, then drain again and check for swarf. I'd then be tempted to do another precautionary oil change after 100 miles or so.
Mine was snapped so far down I couldn't really get anything on it to drag it up, I did make a bit of a hook with an old screwdriver but the bakerlite started breaking off into to chunks so I thought I might as well save time and drill it.
