I seem to remember there's a way to check what choke (fixed, not changeable) your shotgun has. For the life of me I can't remember how. Is there any way to check without a trip to a gunsmith?
of course the best way is to have the bore and choke combination measured with a bore mike to determine the amount of choke it has but here is a rough way to check it to see what choke you have
take a dime and drop it into the barrel from the chamber end with the barrel pointing downward
if the dime stops in the barrel anywhere from an 1 1/2 to 4 inches back then it is a full choke
if the dime travels almost to the muzzle or stops within the last 1/4 inch or so then it is a tight modified, if it falls through but is snug then it is a modified choke
if the dime falls completely thru then the choke is probably improved cylinder or cylinder bore
this is just a rough way of checking the choke designation, so don't expect much from the above
Be SURE to remove the dime before firing the gun as it will ruin the barrel