I know this is stupid. Oh, yeah, I do, but here I go, anyway . . .
Is there more than one version of the rock tip on the jetpack?
The way I match up the angles, it has always appeared to me there are three fins. I was 99% positive of this, but I see so many representations (and even replicas) with four fins, it's got me doubting myself. And I hate doubting myself :)