Thanks!! Did some more digging... turns out PM flipped the positions of the red skid-mounted loudspeakers from below the skids on 3908 to above the skids on 3220 (maybe to get them away from water?). This explains why they changed the shape of the front but the good news is the slot receiving the fuselage insert appears to be the same, so it should work -- and it should look better, because it will be snug as opposed to awkwardly exposed, as it is on the original pontoon helo.