.030 5.9 magnum

I finally got the heads off the 5.9 so I can get them checked before I put a cam and intake on it. Well it turns out it has already been rebuilt and bored .030 over and you can still kinda see hone marks in the piston wall so it's a pretty fresh rebuild,so my questions are:

1- how can I tell if they are flat top pistons vs stock style dished without pulling a pistion.

2-if the heads are good, I'm going to put hughes engine spring and retainers on it. should I go ahead and get a cam from there to? Either way what size cam should I get?

Info on the car '74 Duster full sheet metal, plan on putting a 8.8 with 3.73's under the rear, what ever size converter I need.
I'm still un decided on tire size since I can't find 14'' tires anywhere, and I love my 14'' western wheel mags.
I've heard these engine can do 12's with the right setup and that would be awesome. I'm wanting to build this as a real hot street car.

I'm trying to match everything to the cam, so any help would be appreciated. This is my first engine build so go easy on me.