If this were my car I would first perform a search of local salvage yards using car-part.com to see about local availability and cost of a salvage part. In the Houston area the part is running $50-75. I would then compare the old part to the "new"ish part. Often it's easy to spot the damage.
It might also be a good idea to take the car to a frame shop and have the frame "checked" for straightness before dumping a ton of $$ into it. IMO it's best to know as much as possible about a project as possible before hand. This could be money well spent.
If this car needs a ton of work and there's a decision about IF the project is worth it IMO one of the deciding factors should be WHO is doing the work. It's rarely cost effective to pay a professional to fix a very old car. This sort of project works best when it's DIY.