They are both rated at 1000 FPS. The Blackhawk cost about $20 more than the Phantom. The Blackhawk has an auto safety, the phantom has a manual safety. the Blackhawk weighs about 3 lbs more. Other than that they are about the same. It's up to you.
they are the same gun
You need to contact Ruger. You may have a prototype
$400
Ruger has sn data on their website.
Send it back to Ruger, find a gunsmith.
Ruger has extensive serial number data on their website.
Ruger's website has a sn function.
ABOUT $200-$300, depending on condition, and WHICH version of the Blackhawk.
400
400
Ruger's website has sn data you can access
Ruger has extensive sn data on their website.