Well, call me an idiot, I was wrong. :)
 

So apparently 15 years of not seeing the gun, I was imagining what the engraving looked like, and the condition. The gun had been stored in a closet and the elements have taken hold. About 1 1/2 inches of the front part of the barrels are rusted pretty badly. The serial number is 669**. It says Damascus Steel on top between the two barrels. Has a patent date of March 26, 1878. I'm still not sure of what it's chambered in yet. I thought it was 12 gauge. Anyway, any info that y'all can give on identifying will be appreciated.

Left side of receiver
 

Left side of receiver.

Right side of receiver.
 

Right side of receiver.

Well, from the little we can see it is a D grade damascus gun. Looks to be in fair condition but not excellent. The rust on the barrels sounds scary. Need more photos.

Pull the forearm and then remove the barrels. You should find the grade stamped on the water table. If the gun is old enought it will be marked a grade 3 if a D grade. It may be marked DH or DHE if it has ejectors. on the bottom of the lug will be a number stamped such as 3 or 2 for frame size. Some of these guys can look and see if it is in the book but a partial serial no wont do them any good. they will need the complete serial no. More photos especially of the rusted areas and all no. and letters stamped on the gun would also be of help. Pictors are always helpfull. Nice engraveing.

I agree with fishtail.

Some pictures of the barrel flats, wood & the rust damage would be helpful.

The end of the barrels is the worst part of the whole gun, but I'm not giving up hope that it may be repairable.

ON bottom of barrels where it connects to receiver, left side Pat'd April 12, 1876. Center block 66929. Right side under barrel is a 4 C with a D 41 under and a 3 out to the right of that. I don't see any other numbers. If needed I will try to post pics of the underside of the barrels. I'm having a hard time with the lighting right now to take good pics.

Lighting not too good at night
 

I took the best pics I could with what I have(bad camera).

few more
 

Just a few more. And does have the ejectors

Some of the stamps on the barrel flats are as follows:

D = Damascus Barrels
4 (with superscript)1 = 4 lbs., 1 oz.
3 = Grade 3 or D Grade
1 on the bottom of the rear barrel lug = 1 frame or a light 12 gauge.

As for the 'checkering within the skeleton steel buttplate... someone with a knife decided to "enhance" the original checkering. It is not at all how that checkering would have originally been done.

That rust at the muzzles may clean up but first that rust must be neutralized ASAP.