This is what this threat is about. Actually, about what could be wrong if the RRPM does not droop despite the placard saying it will droop.
As eluded to. You would never expect the RPM to drop at the placarded manifold pressure limit (or even a few inches MAP over the limit) unless you're operating around 6000ft DA or higher in a Raven II, because you are not throttle limited, but instead drivetrain torque limited. So this is totally normal!
In response to your other question it doesn't say anywhere the MAP you'd expect to see at 102% lever down. But st sea level it's around 14"MAP. And he higher the altitude the lower this reading as atmospheric pressure decreases. So around 5000ft it's approximately 11-12"MAP. If you ever see greater than 15" MAP at 102% lever fully down in a Raven II I'd suggest something is worth investigating.
When my manifold pressure line had a problem it was reading 18" MAP on the ground at 102%.