If you're a member of another FMCBC club and already pay an insurance fee for that club, then no, you don't have to pay for insurance twice. Both clubs will still be covered.
Note: The FMCBC is unable to cross reference which members of your club are also members of another FMCBC member club. Therefore, all members should pay their membership and insurance fee to your club unless a previous arrangement has been made. Fee reimbursement is the responsibility of the individual clubs and members, not the FMCBC.