Is it marked "Inland Div", "Saginaw SG" or "Irwin Pedersen"? Inland was the only maker of original paratroopers. Do some research on the guns markings and the originality of the stock... you need an expert to look at it in person, or at least look at a bunch of photos of it. Value can be... under a grand, and well over two grand.
The folks at the Steel and Wood forums
will probably be your best resource for information.
Here's a link
to a fellow with the same question as you... see where that thread goes.