You said you ordered it on-line but did not say if it was new or used.

What I would do is before shooting it I'd thoroughly clean it with a good solvent, a Bronze Bore Brush and see how it looks. If it still looks the same I'd call S&W if it was a new purchase and offer to send photos.

I would DEFINITELY clean it PRIOR to shooting it as shooting it will tend to pack the dirt and debris into the lands & grooves and make it that much harder to clean afterwards.

Any light corrosion and debris SHOULD come out with a good quality Bronze Bore Brush. I'd love to see another picture AFTER cleaning it.