It's $650 in a world in which you don't have tariffs with China.
In a world in which you do, you pay more for the machines, the materials, the components you can't make in the US (a phone is thousands of component, phone makers don't make most of them), etc.
It's probably $650 to design it, build half the parts, ordering most other parts and assemble them.
Now what's interesting with the tariffs is that it's not just it will make the parts you can order more expensive, it will make the supply of such parts available to you restricted since you are now competing with buyers that don't have tariffs and can outbid you easily.
Or course, all this include rare earth supply which China already restricted for US export, so even the part you can make are going to be super expensive. The premium is going to be way more than the tariff ones.
Finally, since you are not going to be able to sell to the Chinese market of 1.5M of people, you will sell fewer phones, meaning your volume effect will be lower.
Meanwhile, competitors from Asia and Europe will be able to sell to the rest of the world, unrestricted by such problems, so much more price competitive and with a more robust cash flow. So you will lose markets in other areas too, hitting your volume effect even more, possibly sending you spiraling.
So, it's definitely pop corn time.