$450.00 is a good price if the gun is in nice condition. Simply put, the choke at the muzzle is what gives a gun it's shot pattern at various distances. A full choke means the shot will stick together as a group to a longer distance before spreading out. Cylinder bore, which is the size of the barrels, will spread the shot out a lot quicker at a closer range. Then you have everything between cylinder bore and full. For skeet shooting, you don't really want a full choke as you want your shot pattern to open up at a closer distance. However, you could have the chokes opened up. If you were shooting trap, a tighter choke is preferred. You do not need 3" chambers for skeet. Actually, 3" shells are not allowed for clays shooting.