Ken, 

I am sorry,  I did use the wrong term.  It is one of the liners that is extended.  

I wanted to let you know how much I admire your work.  I am a vintage knife collector, but if the opportunity ever arises, I plan on purchasing one of your beautiful pieces. 

The screwdriver function would be one of the liners extending forward.  On a three thick usually the liner between the saw and master blade extends for the screwdriver.  Great knife!  Thanks for posting. A lot can be learned from these vintage Horseman's knives.  From the implements to the selection and fit of the stag.

wow now that is a choice knife they knew what they was doing when they built that.....

Thanks, Ken!  It does have all you have said.  One of the backsprings also extends from the top, I think to work like a screwdriver?  It can be seen on the picture with the knife closed..