1929 Browning A5 value or other info?

This is being offered to me in the neighborhood of $500. I really don't know much about them and I would only be interested as a collector item, not as regular shooter though I might shoot it sparingly once in a great while.
What I'd like to know is what the gun is truly worth and what are some opinions of it, for example, is it a good investment and could I easily get back what I invested later if I wanted to by something else? I'm not looking for profit but I like to be sure I'm not making bad choices either!
I appreciate any comments war stories!
Oh and it's a 16 gauge.

Here is the owners description:

This Browning was made in the 1920's, and still shoots like a dream today. Most of the bluing on the frame is gone, in it's place is a beautiful patina. The bluing is intact and shining on the barrel, and there isn't a single spot of rust on the entire scattergun.

It has been modified by Browning to shoot the 2 3/4" shells of today, and it shoots them damn well.

It has a rough stock, with checkering, and the prince of wales grip.

All numbers are matching, on everything from the forend, stock, internals, frame, and even down to the screws.

 

Thanks guys. I thought perhaps because of the age and that I hadn't seen one till now it might be worth something but that answers that. Once in awhile you run across something you're not familiar with and don't want to dismiss it just because it's ugly or whatever. Sometimes you find a diamond in the rough, just not often enough!