Those aren't valve pockets. That's the flash from the camera off the cylinders. I know this because you can see the small dimples in the piston top that face forward on every magnum engine. Magnums don't use valve relief pistons.
As for boost, myself and lots of folks have ran oem pistons to 10 lbs boost as long as the ring gaps are wide, like .030" wide, the fuel rich, and the timing low.
Thanks, LOL I just could not tell. 'splains the odd angles. (Yes I know on piston top types; that it why I questioned it; some looked pocketed and the rest flat! I assumed the OP had it right in front of him.)
The eventual turbo-ing changes the long term game anyhow. OP, you can go either way: short term or long term planning. Nothing wrong with either approach; many just choose to do it once. Getting a summer of fun is a good goal, AND, if you keep it simple, it will be an easier learning experience for you.
I would look carefully at that one cylinder rust spot and see if it is etched deeply into the bore once you get the rust all off. Make sure you get ALL the rust particles off; most metal oxides are very good abrasives.....
