Yes there are spacers used between the caliper and the strut mounting "ears" depending on what your rotor hats require to center the rotor.
http://forums.pelicanparts.com/porsche-911-technical-forum/769679-930-calipers-there-more-desirable-year.html#post7688331
On my current setup I have 930 front calipers, 32mm thick rotor with zero offset (Wilwood HD40 11.75" x 1.25"), 1/4" thick flat hats that are fixed/non-floating bolted. I needed to space my caliper to align it with the rotor so I bought the four Porsche spacers instead of stacking 1/2" dia. grade 8 washers or making my own spacer from 1/8" plate steel. They were only $4 each and I was placing an order anyway. The part number is 930.351.553.01