EDIT, just realised its an alox,,, silly me.... I would imagine it would still be a simple enough job to dremil off the rivets heads, allowing the removal of tools. Sorry I can't be of further help.
Hey. I am guessing you want to remove said tools from the knife, and not add any others right? If so, it is easy to remove the plastic scales, by gently prising off. Be aware though, that they probably wont go back on securely afterwards, so you'll need to glue them, or just replace with nice wooden ones, again a very simple diy project.
The tool removal will be a case of filing off the rivets, remove the tool in question and replace the rivet. It is also a simple diy tast to fashion new rivets too. Having never removed a rivet from a sak, I can't say if it would need a spacer instead of the tool, or if the rivet has a thicker central diameter, which would allow the metal frame to sit square and spaced correctly apart for the remaining tools.
Please bear in mind I've only tried running this through my mind, as to what would be involved. I've only ever replaced the plastic scales on a couple of my own saks. Which is well worth the effort.