If you can measure continuity from those tabs to the tip, then your soldering iron is grounded.
Otherwise, it will be a little more difficult to solve the problem. Long time ago low signal mosfets' gates didn't have any protection at all, so we used to short circuit all the terminals, using a fine bare wire, before soldering them. Applying the shorting wire to the leads was done on an ESD station. That took care of protecting them from non grounded soldering irons. Don't forget to take out that wire before powering on.