IMO:
I think that the 177 does not have the "fingers" or the regulator handle. It was strictly eye measure.I have found a couple that were missing these parts, but they were also missing the ID tags.I just picked up a 117 that was locked in at 10 gallons. Someone ran the overflow tube all the way up and then sawed or broke off the regulator handle, closed the door and bent the lock tab back so that it(the door)could not be opened.Perhaps the positive stop adjustment was a nuisance...thus giving birth to the 177 if I am correct. I have found many 117s in similar conditions.
Dave
