Yes, these have been modded but they are indeed xxxxxxx-rare items.
The added multi-terminal covers the bass-reflex port and it seems one of the super-tweeters was damaged when doing the mod'. It isn't clear if this has been repaired or not... (owner's homepage : http://homepage3.nifty.com/stonetechno/s-f1.html)
The serial numbers posted (CJ-00111 & CJ-00115) indicate a much higher production run than I had imagined ! Where did they all go ???