So, the S/V and bushing are still stuck together?
As long as they are stuck together I don't see how
the bushing can fall in. On the other hand, is the
bushing threaded or soldered into the boiler? Hmmm.
I think you might consult with Andy at Jensen
to find out if the 'bushing' could fall through
into the boiler. I looked at my riveted boiler
to compare and I couldn't say for sure one way
or another.
Good Luck,
Wayne