Moreover, Hedy Lamarr was the one who had the idea of using FHSS, not being aware about the unknown patents where the same idea had been proposed earlier.
The contribution of Antheil has been in the practical implementation of her idea, so it would be ridiculous to call it "Antheil's patent".
There are plenty of inventions like this, where one inventor has the idea on which the invention is based, without having enough practical experience in that domain to complete the invention, so a second inventor with appropriate experience is brought in, who may be the author of the bulk of the practical implementation, but who is not the author of the original idea.
In such cases, both are rightly called inventors, as none of them could have completed the invention without the other.