Hi there,
it is possible to modify the 232. A friend of mine changed the sapphire crystal with the plexi of a 249.
He even changed the caseback to make it look more like a 3646.
Here the link, sorry but the text is in german:
http://www.watchlounge.com/wbb3/wl/watch-lounge/panerai/104921-232-mal-anders/
best, Josef Falter