Harbor is a Latin word; -or is the correct Latin suffix. It was correctly used in English at the time of the great American split. Only in the 1800s did English people decide to become French and erase over 2,000 years of linguistic history with their newfound love of the French -our.
Any conservative English person would also spell Labor Party in the long standing correct English spelling of the Latin word labor.
In summary, please use the correct traditional spelling, not some modern Francophile thing you have going on. You're embarrassing to the proud Anglophone world.