In short, no. The number of assets not created by you or created outside the jam window do not impact the rating.
We're going to do our best to judge each submission based off what was created during the submission period in an attempt to keep everything fair. We've been doing this long enough that we have a pretty good idea of what's capable to make in a week's worth of time. But listing what was created prior to the jam/not by you helps remove the guess work on our side. So, if you create a game with 100+ listed model assets from an art pack that you purchased, then we'll adjust the visual category to judge you more on how you put all those assets together (e.g., the composition of it all, the lighting, how they enhanced the mechanics of your game, etc.) Rather than the models themselves.
The project does not have to be publicly accessible. We'll only be judging your submission. E.g., the .exe/.apk that you upload to itch.