I'm guessing here but it appears you have one of the early '71 Panteras, perhaps a pushbutton model, that had removeable spindles from the front upright and integral steering arms, while later cars had integral spindles & removable steering arms. If so, know that those were only on the first hundred or so cars, none of which were ever officially imported to the U.S, so chances of finding a wrecked Pantera of this type are slim. Possibly, the factory Gp-4 & -5 racers also used this assembly (of which there were maybe 30 total). Far as I know, the early & late suspension uprights were specific to the Pantera.
Any decent machine shop could make a spindle, even a high-school trade school or night shop-class with a metal lathe, but if you're in CA, good luck convincing anyone there will be no liability to them if your wheel ever falls off.... Perhaps a local sprint-car prep-shop would do it, being used to building race cars. Especially if you have your old one for a sample. Optionally, it may be cheaper/less hassle to find a later model front upright assembly with integral spindle and do what you have to, to adapt it to your car.
What area are you in? I do know of a basket-case Pantera with one each of the two possible front uprights & he doesn't really care which his car has but he wants two the same just for simplicity. But I'm not sure which side has which type. I'll check into it....
Jack DeRyke, PI Boss Wrench