I purchased a model 660 a year ago and it had 4 sets of gallon markers; attached to the top of the cylinder ring and attached with brackets at the bottom.
I just purchased another 660 and it has 4 sets of gallon markers, 2 attached the same way as my first 660 and 2 sets of markers attached to 2" diameter aluminum pipes. The pipes are filled with factory cut pieces of woid.
According to serial numbers, my 2nd 660 was built 1460 units after my first.
Has anyone ever seen the markers attached to dummy pipes.
What purpose is served by the small blocks of wood inserted into the pipes.