This is a great drop weight machine, probably one of the better ever made, including today. It is built like a tank and has a double turntable for ease in stringing the crosses. The Alpha Pioneer III is the same machine as the Gamma 600-FC, and the Tenex 600-FC, manufactured until the early 1990s.
The machine pictured does not have the original Alpha clamps and is missing the four side supports. There is also a series of nylon head and throat adapters to allow a better mounting of various frames (two, one head & one throat) are shown in the pictues. You can probably still find these pieces at Alpha (newtechtennis) or Gamma. I do not think new clamps or glide bars are available, but you may be able to find used ones.
With all of the parts, this machine is equal to any dropweight out there today, with the exception of the S t r i n g W a y tensioning arm and is much superior to the Gamma X2, Klippermate, SP Swing, etc. It is limited in frame headsize and fan style paterns (will accomodate 110 sq. in.).
Do a search and you will find lots of information on this machine.