They're straight pins which are swaged into the links and aren't meant to be removable, unlike the other pins/screws in the removable links.
You could try a pin punch, but I fear that would break before the pin gave way unless you use a quality item.
There's only one way to find out.
Support the bottom of the link in a bracelet block, apply oil to both ends of the link and use a pin punch and a hammer.