Chassis Rail With Wide Holes on One Side and Really Long Holes on the Other Side

This video: Tutorial 2: VEX Structural Components - YouTube
At 5:55, the speaker in the video pulls out a special type of chassis rail. We have it in our inventory of parts, but I’m trying to model our robot in solidworks and want/need this part for a trainwheel-type indexer. It’s not in either of the two vex parts libraries I have and this video is the only place on the internet(including vex’s official website) that I have been able to find this part.
What is it called, so I can find and download it?

Cortex and earlier kits had the angles. You can still find them in the old steel booster kit. So they’re legal