If you get a scope, bases, and rings from someone like Leupold they should all pretty much match each other. If you get a gun, bases, andrings from the same manufacturer like Sako, they will match. Matching every thing silver is where it get's tough. Even matte black have different sheens and don't match perfectly. It's about as close as it gets though.
I just got a scope and rings/bases for my new gun today.
http://img.photobucket.com/albums/v701/Worc/Sako1.jpg
http://img.photobucket.com/albums/v701/Worc/Sako2.jpg