Could be. I'd suspect our old friend, the bulkhead connector, first, or maybe just a bad/ loose/ broke connection at the coil side of the resistor--where the bypass wire hooks in.
If it's a bad switch, there are a couple of ways "around" the problem, without replacing the switch.
1 You can hook a nice big diode to the "start" terminal of the starter relay and run that up to the coil
2 I found out that some later Mopar starter relays have FIVE terminals, one of them does the job of the old "bypass" circuit in the switch