American Muscle sells tubular upper and lower control arms for $170 I believe. So I would go with that since you are going to have to put some on anyways. But I would get some on there very soon factory or aftermarket.
That's really weird. The only thing I can think if is that the previous owner was going to upgrade it and had the wrong parts and never but the stock back on or they took them of with intent of putting better on but sold it before that.