Google.
70-100 years.
It is a single barrel, break-away 12 gauge shotgun.
depending on the make, age,and condition that shotgun could be worth nothing up to $3000.
There is no "break in" shotgun. A "break open" shotgun is a single barrel, double barrel, or combination rifle/shotgun which breaks open in the sense that a lever will unlock the action, allowing the barrel to pivot at a hinge at the front of the receiver, pivoting the rear of the barrel up to expose the chamber. A shells may be loaded into the chamber and the barrel pivoted back to close the action. The act to "break in" a shotgun means to fire it a few times to loosen it up.
Seek the services of a good gunsmith
The Remington 90-t is a 12 gauge, single shot, break open, trap shotgun
my serial#i s 612fb
$50 and up, depending on make, model, and condition.
No published sn data
The CBC MODEL SB 410 BORE SHOTGUN is made in brazil and imported by firearms import and export Corp. located in Miami, Florida it is a break-action single shot shotgun
Assuming you mean a top break shotgun, there were several models, prices will vary. For a single barreled top break, about $70-$75