Check your Cowl for a color match. Mine did not match. One was True Red and the other was Missle Red. Don't remember now which was needed?? Tower sent a new one that almost matched. They said there was a mix-up in China.

I like my OS 46, and 55 2 strokes. Iv'e had 2 OS 50 AX that ate rear bearings. I sent the one back to OS twice in 6 months, about every 100 flights because it sounded like a coffee grinder. I think there was a problem with the OS 50's so they reppaced it with them 55's. In fact when I sent it back the second time the sent me a 55 instead of fixing it.
I still have an OS 50 on a MOJO that is on it's 3rd set of bearings. There easy to change and a set that costs about $10.00 at the Bearing place. I Use a lot of after run and it's lasted 200 flights?

When you get a good belly pan. Reinforce the forward cut-out with a thin sheet of balsa. Then when you pick up the wing from the front you won't run your finger through the Mono-Kote.[:@]
I repaired mine with some Trim-Sheet. it's heavier then Mono-Kote.