Truly if alignment is that mission critical for you. A jig would be the best bet.
At any rate. I watched the video again and grab this screen capture.
CSI Enhancement Zoom:
There is a lip on the left and right hand side. The reason why there isn’t lip in the front or rear is for the passthru feature on the Pro. I’d assumed they’d use one part number for the work area/bed in both models for manufacturing/costs reasons.