I would agree that the $500 ‘special’ won’t match the 1920 style. They do make deluxe wood looking metal sectional doors which would look correct but are much more$
Is your existing door a single flat door (1 piece)? Does it open straight? Are the hinges bent? Is it hard to lift? Will it stay in the up position or close a couple of inches?
Springs are easy to replace. Just measure the gauge ( wire diameter ) and the length. Prop the door open with a ladder to unload the spring tension. Get a friend to help you unhook the bottom of the spring by pulling down. Replace with new. Done. By the way, all springs now have a wire extending through the center to prevent a broken spring from flying.
Actually, if you door is still in good shape you could fish a wire rope through the existing spring to make a loop and clamp the ends together to safety tie the spring.
If the hinges are bent or not secure then you will probably be easier to hire a door company. Parts are not that much if you want to diy but remember the door is heavy and unwieldy.
If they do not make your spring now, I’m sure you can find an equivalent. Even on-line. With the gauge and length (maybe counting the turns too) they can look up the tension and match. It’s not rocket science 😉
