sadly yes.
Disconnect the lot, and put a resistance meter between heating coils and earth., There should be NO detectable resistance there. If there is its definitely new coil time. If there isn't, sadly it doesn't rule them out, because they might short only when hot.
I hate intermittent faults. The Freelander had occasionally failed to start for 18 months, until one day no amount of waiting, thumping the bodywork near the fuel pump etc etc made it do so. Finally, I thought, we can trace this fault..and know we have found it. New fuel pump and off she goes.