Thank you for your comments everyone.
Dunster, no, I did not see that article regarding comic book boards and their archival qualities. EXCELLENT article - thank you so much for sending the link. It certainly confirms my thoughts on some of the boards.
I just moved to a new house and so I have the opportunity to set up a fabric storage system as I unpack. I am not concerned about wrapping fabric around plastic since the Polar Notions boards are plastic. However, I do not know enough about plastic wrap (Saran Wrap) to feel comfortable that it is suitable for long term contact with fabric. Wrapping the boards with muslin sounds like the best solution for me. Thanks for that suggestion.