Hi Jordan,
Please find below a script that retrieves the Filled Region edges line styles. You could look for a specific line style and get the filled region that contains it. The only problem I’ve found, is that I was not able to change the line style of a single edge and this could not work for you.
The line style is stored in the Geometry.Element EdgeArray parameter. (If you haven’t done it yet, please install RevitLookup as it would have been impossible for me to find a solution without it).
I should also thank Dimitar_Venkov as I copied the code to access the element geometry from this post: Element.Geometry node (from Revit) to Python Script