How do I know which characters I level boosted?

Draenor and Echo Isles
1

I’m wondering for heritage armor reasons. I’ve given some of my characters level boosts but I honestly don’t remember which ones. Is there an easy way I can find out so I don’t spend a lot of time leveling them to max just to find out they’re not eligible for heritage armor?

2

I couldn’t find any way in-game or through the API to say that I definitely boosted, but check the leveling achievements. Mine say I went from level 60 to 110 in the same day. While it is possible, it’s not likely that I did that without a boost.