First of all congratulations for your purchase, the A3000 is really a great machine... my favourite Amiga!
Regarding the mobo, I don't think there are significant differences between 9/02 and 9/03.
My A3000 has 9/02, too.
Have you ever thought to solder two wires on the mobo and put the battery in a safe place?
In this way, if it leaked, it shouldn't damage anything!
Alex
