MST XXX-D RTR - broken knuckle :(

Hey everyone, 

New here, just picked up a XXX-D RTR from Hobbybest on Ebay, and very happy with the car.
Today, I let my friend have a go at it and he owns a Redcat, so he knows a little bit of drifting.

Long story short, he slid into a curb slamming the right rear wheel breaking the knuckle 
attached to the lower control arm. So here I am looking for some advice.

I looked at the options booklet and found a aluminum replacement Part# 210354. I'm having a hard time finding red aluminum parts for this chassis
I was wondering if anyone here knows if knuckles from the FXX will work with the XXX-D even though part number is different (820111.) 

RCMART states for 210354 works with FXX, FXX HT / 820111 works for FXX. Parts look identical.
On MST's website, 210354 is 'for' RRX, FMX, FSX, FXX, XXX. 820111 is 'for' RRX, RMX, FMX, FSX, FXX, XXX.

Please help!

Thanks.