should there be anything between my camber plates and my strut tower ?

my coilover upper mount camber plate mounts directly onto my strut tower (3 bolts right up to the strut tower) .

I know my old, former OEM strut upper mount assembly had all types of rubber bushings in between.

is this normal ?

yes.

infiniti sedans usually have a thin paper gasket between the two.  if yours had this, id reuse it to minimize the squeaks.  if it didn't no worries.

and never think aftermarket/performance suspension pieces improve the comfort/quiet ride of the vehicle, ie lack of "all types of rubber bushings"

when I had my JICs, I used a thin slice of rubber as a spacer between the camber plate and the strut tower...definately eliminated a number of squeaks and thumps.