No, I hadn't but fair play to you for noticing them! Awesome!
I personally found this episode lacking, most probably because we saw so few of the main cast ('mane' cast, even...). The mystery, as people are saying, was way too predictable. I knew it was him as soon as the problem was first addressed. The concept of mystery / case-solving episodes is a good one, but I feel they just need to get us thinking a bit more. Now okay, this isn't Agatha Christie reincarnated or anything, it's still MLP and they obviously can't go into any serious crimes, but the culprits should surely be kept more subdued than this. MMMystery on the Friendship Express had a relatively unsatisfying ending as well.
The Rarity detective scenes were amusing in their observing of classic detective films, but they did drag on a bit. It felt like the solving of the case was just suddenly thrown on us by Rarity at the end, and we saw relatively irrelevant endeavours in the detective scenes - ideally we should be invited to 'think along' with Rarity, as opposed to watching her and moaning Rainbow Dash carry out meaningless acts and then having the verdict delivered at the end with us clueless. Maybe people disagree; it's just how I felt watching it.
I also don't feel like the Wonderbolts would so willingly be prepared to kick Rainbow Dash out from any affiliation with them at all after everything she's done for them, and how proven she is to them, instead giving her a rash ultimatum. Talk about a fair judicial system in Equestria...
Nevertheless, as a Rainbow fan myself , it was great to see her get an episode focus. She seemed unlike herself though, almost too dependent on Rarity's help and unwilling to take matters into her own hands - like she might normally and arrogantly do. Character development, I guess...anyway
Keep going, MLP, we still love you!