I'd say it's number 7 in this tech illustration...and note either side is same part number.
http://parts.autonationtoyotasouthau...ents-rear-scat
On the phone, a parts person would make sure you get the proper clips needed, to retain the piece.
Appears to me that you'd need three parts numbers X two each of them. Six pieces total.
Left and right are identical.
Edit: You might want to check it out in the spring, Like April 2017, maybe May, after the shitstorm of salt is over with. Been there, done that.