If those two paragraphs are direct quotes from the by-laws or CC&Rs, then you've omitted the most important paragraphs:
The definition of "Unit" and the duties of the unit owner with respect to the "Unit."
Having read hundreds of condo documents in my time as a property claim rep, my guess would be that the Board is correct and the windows and insulation are up to you.
However, I will reserve my final opinion until you have quoted the provisions of the documents that I requested.

