If you can find a pair of low profile speakers, they may fit; but I don't think you'll have enough clearance.
Then again, I'm not sure how much room there is between the headliner and the roof in a fifty-two. The best way is to pull the headliner and measure.
As for the mounting, I would mount them to the headliner, wire everything up, and then remount the headliner.
But that's just me.
