The problem you will have is you can NOT contract this flagpole legally without YOU having the contractors license.
Hopefully the city will stop you before any damage is done or are you going to have your installer pull the permit since he has the contractors license? Don't take his word for it, there is an online database where you can search if it is active..
So, say you sell the flagpole to this guy, you have a contract, have it installed, when its time to get paid, he does not have to pay you. Take him to court, the judge will ask, do you have a contractors license (they will not care if your installer does) Then the other legal crap....
Directly from the State Contractors board...
Contracting without a license is usually a misdemeanor, carrying a potential sentence
of up to six months in jail and/or a $500 fine, and a potential administrative fine of
$200 to $15,000. Subsequent violations increase criminal penalties; if there is a prior
conviction for contracting without a license, a fine of 20 percent of the contract price
of the work performed, or a $4500 fine shall be imposed. Also, the unlicensed
contractor shall be confined to jail for no less than 90 days.
Felony charges may be filed against those who contract without a license for any
project that is covered by a state of emergency or disaster proclaimed by the Governor
of California or the President of the United States. Felony convictions may result in a
state prison term as specified by the court.