Does anyone know what type of bolts these are I took them out from the battery tray f-150 1984, did someone did this custom or they come like this?

 

They are self tapping bolts. They are made like that.
The bolt creates the threads in the hole as it is tightened.
They are common when something is bolted to sheetmetal and saves a step during vehicle assembly.

They are not for thick metal, castings, forgings etc., but can be used if the threads are already formed in those parts.

 

Once these are removed the threads in the mating part will remain, meaning that the new bolt does not have to be the thread cutting design a regular bolt will work.

 

Thanks for the help everyone