Hi Rusty,
I will take a stab at this. I believe that very early LA40s didn't have a boost port. I have never seen one myself, but it has been reported on the forum, I think. The piston problem puzzles me a little. I have never given it much thought, but I was under the impression the LA pistons were cast and then machine finished. More than likely wrong on this and I am sure someone will come up with the correct answer.
Regards,
Andrew.