No. Absolutely not. The spreader tool is to simply ensure that the awning channel is kept the right shape to make threading the awning through it as easy as possible. A silicon spray into the channel helps although most half decent furniture polishes in a spray can do the same job.
I certainly wouldn't do what you are suggesting, especially on a new van. It's a job I'd get a dealer to do if you really feel that you can't thread the awning as it is, but it probably just needs a bit of practice on your part. I'm sure that the manufacturer will have tried an awning on the van, and fitted an appropriate rail to suit.