I also have one of these boards!
I posted about it here: viewtopic.php?p=327344#p327344
I actually soldered in some audio out sockets. The board looked very clean, as if they had not actually been desoldered, but came without them from Atari maybe?
My ROMs have different stickers on and you seem to have a few more mods to your board.
I also have smiley faces instead of bombs and same logo when booting, but it seems to work ok otherwise.