I did a little test. While picking up the "Pinking" blade, Joann's had a sale on Olfa cutters and blades at 50% off. The only pinking blades they had in stock were the Olfa. I have a Fiskars already.
Since the sale was going on, I bought the blade for $5.99 and the cutter for $8.99 which I thought was a great price. I figured I could keep one cutter with a regular blade and one for the pinking.
This morning I took the pinking blade and put it into the Fiskars. The Olfa blade has a little notch on it, however the Olfa cutter was round with no notch. I can't figure why the notch is on the blade.
I tried cutting with the pinking in the Fiskars and it worked.
Then I placed it in the Olfa and it worked even better.
Don't get me wrong. It did work in the Fiskars cutter, it was still a pinked seam. However the cut was a lot cleaner in the Olfa cutter.
I guess the answer is Yes they are interchangeable, but work the best in their own cutters. Not very scientific, just my humble opinion.