That's interesting. Ours too. It fires right off. Our 310SG TLB came with 6000 hours on the clock. It was used daily in a very cold climate by a concrete demolition company. From the factory they ordered it with factory block heater, fuel heater, remote ether injector, and a dual battery system.... but no glow plugs.
The only one of those extra cold weather systems that we use is the low wattage standard block heater - the same block heater our 16 hp Yanmar has.
During power outages I've started that 90 hp JD 310 often at 0*F or below without any preheat at all. I don't like to do so, especially after it has been sitting a few months - but sometimes there is no choice.
Like your JD 410, It fires up instantly - sometimes so quickly that it needs close attention to hear the starter crank. Settles down to a smooth idle and no unusual noises. None of our other diesel tractors or trucks starts half so well.
Whatever JD did to make their engines last so long has sure worked out. My buddy has a much older JD310 which starts and runs as well as ours.
rScotty