Happy to see you're considering contributing!
I hope that folks will add important features and fix defects and shortcomings in the code. When they're adding features, they'll do it in a way consistent with the way things are done in the existing code. They resist the urge to rearchitect and rewrite everything in their own image and instead put their efforts towards maximizing functional improvement while reducing source code thrash and change.
When working in a routine, work in the style of the routine. When working on a file, work in the style of the file. If those are inconsistent, do whatever minimizes changes. Stylistic changes should only be introduced after discussion in the group, and generally should entain owning that style change across the entire project.
If you can make PET Rock run and connect to the outside world on the Commodore PET, by all means go ahead. I may even be willing to bend some of the other rules a little. :)