1) Are there any complete PDP-6s anywhere at all?
There are none known to exist
2) Does the Computer History Museum in Mountain View have any PDP-6
artifacts?
CHM has the Fast Memory chassis from the Stanford PDP-6
3) Are the stories about the Boston Computer Museum receiving a
complete PDP-6 and then chopping it up to sell as gifts truth or
urban legend?
Ken Sumerall and I worked on putting this rumor to bed about six
months ago. There are no records of BCM ever receiving the PDP-6
from Stanford.
As best as we were able to determine, the Stanford PDP-6 that was
shown at DECUS for the 10th anniversary of the 36 bit product line
was sent somewhere within DEC, it was NEVER sent to BCM. When Compaq
donated their museum holdings to the Computer Museum History Center
the Fast Memory chassis was sent. There is no evidence of any other
part of the system (or a rumored additional PDP-1) surviving. It is
unknown what happened to the rest of the PDP-6. We do know that we
don't have it.