I can't tell from the picture if that is a genuine star gauge marking or not, but it really doesn't matter. It doesn't even matter if the barrel is original to the receiver, or if the gun was originally a National Match.
Today, now, it is simply a sporting rifle built on a heavily modified M1903 action. Period. Value is probably around $500-600, a lot less than if the guy who took it to a gunsmith had left it alone.