Wow...thanks for all the info, special thanks to Light and Milnoque.
It is definately a J50. Inside the body is a stamp that says J50, and then on the neck block is the serial number.
The guitar looks basically like this one:
http://www.provide.net/~cfh/j50_63.jpg
Except the pickguard is different (it does run down the body as far as the one in the photo does)
The color also seems a bit different. It's not a sunburst color, it is natural, it just looks like it has more of an orange hue to it than the ones I see in the pics I have found.
Here's the website where I found info about the serial and FON numbers.
http://www.provide.net/~cfh/gibson.html#serial
The serial number on the guitar was something like 4175 28.
I'm not sure if the numbers are exact with the exception that I know for a fact the lead "4" is right, and the "28" is right. I didn't see a hyphen in there anywhere.
On that website above I must have taken the 1941 year off of the Serial Number section that describes mostly lap steels. I guess i didn't read very carefully. If I scroll down a bit it shows that the 4000 range serial numbers are also associated with 1950 Gibsons. So I'm guessing it's a 1950.
The guitar would probably be valued at the low end of whatever range is presented because, like a lot of older instruments, it has a visible crack running through the top. It's a shame because its a beautiful instrument, and it sounds great too.
When I was at their house I changed the strings and used a light application of wood cleaner to get the grime off it. I assumed that was ok, I don't see why it wouldn't be.
Any advice on what to do to help preserve it?
Thanks a ton guys.