Thats a personal decision. I had my engine shipped from Canada to Hawaii and chose to get insurance. It was about $500 and the engine arrived without incident.
Don't bank on this! Auto policies don't typically cover personal property, you'd rely on your homeowners insurance for that. However, most homeowners insurances specifically exclude airplane parts (Thus the market for builders insurance).
I'm not sure where you would get coverage: if your homeowners could issue a rider covering the engine, or if a builders risk policy would cover it? But if you're going to make assumptions I would assume it's NOT covered without a specialty policy.