The easiest way to tell if your gun has a firing pin block is to compare yours to the diagram at the top of the HOME GUNSMITHING club section There are two variations shown.
The gun proper is a 75/85 without the firing pin block. (Other minor differences are shown for the 85 Combat.)
The inset diagram at the top right shows the variations for the "B" version. In the inset, you'll see a roll pin through the rear of the slide, in the serrations, and if you take the slide off, you'll see part of the firing pin block plunger from under the slide (part 58 ) . If you've got the roll pin, you've got the firing pin block.
In the 75/85 non-"B" guns, a firing pin stop is used to retain the firing pin. (This is part 56 in the diagram.)