No, actually DB and pretty much all the rest of the Masters class (FAI) pilots only used 3 blade props in 1983, which was the first year noise was measured and limited. It was also the las year of ballistic pattern in FAI. They were used by some (me included) into the next few years of turnaround pattern too.

Other than that last year of ballistic , virtually everyone used 2-blade props. 2-b props are definitely the props used in the ballistic pattern era.