For my daughter, yes. She wears the same size (Child Large) in both. However, I find the GK leotards are almost always a little bigger on her -- so if your daughter is almost ready to move up a size in GK, then quite possibly you will need the size up in Plum. Make sense??
ETA: Plum has become my DD's absolute favorite leo brand -- I think your daughter will like them!
My daughter loves plum, she wears a CL and also a CL in gk, but some GL CL's are a lot bigger. I would say that Plum's are cut slimmer? For reference my daughter is 4'7" ( i think could be a bit shorter ) and 67 lbs. which is all muscle ( she is on the thin side, but compact if that makes sense?)
Plum confuses me...it’s like the incredible adjustable leotard. We order axs but she is still rockin a couple of mediums and all her CL. I look at her in the axs and think maybe I should order AS for growing room...then she’ll go and wear a child medium then next day
I think Plum sizing depends on how long your child’s torso is. My younger girl has a short to average torso length, and her Plum size is the same as GK. My older girl with a long torso can’t even wear Plum. She is an AM in GK. Plum AM is too small and Plum AL is way too big.