We don't really know though if that rollbar is an integral part of the cargo kit. On the SUV kits, it looks to make up the framework that the flat panels that the sides and roof attach to. It might be possible that the cargo kit doesn't need it, or uses a lighter frame without airbags in it.
What we've seen appears to just be an SUV kit with the windows wrapped. The final version might just have solid side panels without window shapes.
Let me reach out to the rep who answered my question back in August and see if there's any update.
Edit with reply from Yolanda:
"Thank you for your message and congratulations on reserving your Slate!
Your conversions sound fun!
As we get closer to production in 2026 we will confirm the exact details of the accessories and SUV kits - the basic differences between the SUV kit and cargo are similar to what you described - stay tuned for the details to be confirmed soon - we're excited!
Let us know if you have more questions - we're happy to help!"
In my inquiry I described the SUV kit to include windows, insulation and etc, and the cargo kit to have none of that. My focus was on the shell.