Yes, it gave me a pause too. The trick is "our factory" represents current factory state, but it was not claimed that it has been "our factory" for 60 years, just that it operated for 60 years. Indeed, they took over from previous owner, but Musk puts it in a way that casual reader may conclude they somehow contributed to the whole lifespan, which is not true, obviously. Still, the larger point - that the factory can provide jobs and tax revenue long after the credits expire - is valid.