I did think about the thread length on the bolt. I’m pretty certain the threads are roll formed, but if you needed more threads I would think a die could be used to extend them. Rolled threads are generally stronger, but also cheaper, so I’m not sure if more strength is really needed.
It has been years since I’ve used a die, but I think it could be done fairly easily.
I know all of this will go far beyond $13, but there might be a point in time where you are glad you spent more.
John