For the service that seems to be presented, the cost looks to be very reasonable. Maybe a nondestructive testing recommendation at a fraction of the cost could come of it. You may, but I don't think, you'd see much of the damascus pattern on an xray. If the alloy components that cause the different colors are able to be distinguished by xray, I think the image would be muddied because it likely lays at random diagonals through a section of barrel. As you noticed though, most of the defects do not seem to follow the damascus patterns.