Yes. The "12 Volt" Delco coil is actually designed to operate properly at around 9 to 10 Volts DC. If it's run without a resistor the points will have a very short life due to excessive current flow. During a cold start, the battery voltage will drop to around 9.5 volts, so with the proper resistor bypass circuit in place, the coil will still provide a good spark.

BTW, the myth about the "hot blue spark" that everybody considers to be ideal went away in the mid 1960's when Delco started using TV/Radio suppression cable (TVRS) instead of copper-cored spark plug wires. All that metal-core wire does is cause distributor caps and rotors to burn out prematurely.
Jerry

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