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Yes, you don't want to isolate the zincs....
Technically the teflon is really there to act as a lubricant/friction reducer and the tapered threads should seal themselves by design - but the tape will of course make up for some flaws or lack of tightening and is routinely used to reduce the possiblity of leaks.
An alternative to tape, especially if you are dealing with a system where you don't want an errant piece of the tape to enter the system is a teflon-based paste-type sealant.