The originals use a "short" in the system to wind the clock. Basically a little pos and neg spark touches and the small short explodes to wind the system. The only thing an original clock will do is tell you what time it stopped working. If you have an original clock the best thing you can do is unplug the battery when in storage / winter.
One way to tell if your clock has been updated with new guts is to see if it "tic / tocs" with the second hand (that's how the originals worked) or if it's been updated it will operate the second hand smoothly.
"manufactured to original factory specifications" means the clock works are the original 1970 technology ?