Just looked at a friends boito 12 ga...the front wood forearm (attached to the barrels) needs to be pulled off first, like most double barrel's do. Then slide the lever to break open the breach....
I would look at the number of barrels. If there is more than one barrel, you know you have at least a double barrel shotgun. If there are 1 or less barrels, then you don't.
Some people claim a .410 double is worth up to $500, but it would have to be like new with the original $15 price tag still attached. More likely to bring about half that much if still functional and...