'*' designates full choke (F). '*-' designates improved modified choke (IM). '**' designates modified choke (M). '**-' designates improved cylinder choke (IC). '**$' designates skeet (SK). '***' designates cylinder bore (CYL).
Contact Browning.
Your browning superposed was made in 1933.
With the serial number that you provided,your Browning superposed shotgun was made in Belguim for Browning in the year 1955.
Superposed
Your browning superposed was made in 1968.
'*' designates full choke (F). '*-' designates improved modified choke (IM). '**' designates modified choke (M). '**-' designates improved cylinder choke (IC). '**$' designates skeet (SK). '***' designates cylinder bore (CYL).
Yes. A lot of choke manufacturers like Briley will also. Check with a gunsmith in your area as some have become really good at it.
No, they are not.
Receiver
The 72S suffix to your serial number indicates that your Browning superposed shotgun was manufactured in the year 1972,by FN of Belguim for Browning.
You will have to call Browning.
Impossible to tell without pictures.