is caulk considered “hardware” or would it be illegal
Are you still reading the version of the rules that reads “hardware”? You’re about 6 versions out of date. You have to keep up with Team Updates: http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=450
Rule <R92> now reads:
S. Mechanical fasteners (e.g. screws, bolts, etc),
That would not include caulk.