Your SAK is either a Huntsman or Fieldmaster, depending on whether there is a corkscrew or Phillips on the back. The ballpoint pen comes in the "plus" version of scales, and is pretty common (standard on Compact, Yeoman, Swisschamp). You can get a feel for the value of the SAK by looking at prices for a Huntsman. The sheath kit is not very common, but is not extremely valuable, in my opinion. Maybe, extra $15-20 or so.