You have a 10 gauge, grade 0 top action with plain twist 32 inch barres. It is built on a #3 size frame.
I agree with George, a gunsmith could turn this into a nice gun if the barrels are not heavily pitted.
You can do some work yourself
but be gentle, no sandpaper or steel wool. Get the light rust off and the old dried oil crud and it will look much better fast.
See the FAQ's link and the Parker Identification links off our parkerguns.org main page (left side). The forum thread
http://parkerguns.org/forums/showthread.php?t=8033 would be of interest too.
BUT, DO NOT OVER DO IT. Just clean
it without taking away patina or send it off to someone like Brad.
Enjoy!