Karl
Karl,
The pictures you show us suggest this 606 lies in the 1971-75 timeframe. If it has the 3-wire cord (with the ground prong on the male plug), it will be from the 1973-75 timeframe.
And yes, it is worth buying since these commercial-grade cleaners are getting very scarce now and this one appears to be in great condition for its age.
~Ben[this post was last edited: 2/2/2019-00:29]