[GreenKeys] Model 15s with bottle caps for feet

[Henry Eck]

I and at least one other greenkeys correspondent have model 15s which
have bottle caps attached (open side down) for feet.  Both machines
were retired from the Associated Press.

No labels on the bottle caps, just bare metal tops, but they do have
cork inside.  Perhaps this might have been a way to prevent the
machines from walking due to vibration (?)

Since there are at least 2 machines with this enhancement, I just
wanted to ask if anyone else had seen this or had the explanation.

Thanks.

Henry Eck