Yes, the slots are molded as part of the chassis tub.
Makes it a bit more challenging, but I figured if the factory folks could do it, I could too. :cool:
I started in the outside slots, pushed them straight thru then fed them into the tray from underneath.
The inside slot next to the drive-shaft tunnel was the trickiest for me, but I did the same thing, pushed them thru the bottom, then reversed the end and pushed them up thru the chassis. The...
I put longer straps in mine, but they threaded thru the existing slots without too much grief. A pair of thin needle nose, or good tweezers might be needed. The straps I used came out of an Aarma 3s model, IIRC.