I am not familiar with the Scott catalog and it was difficult to find and identify this strip of 4 stamps
Perforation is 11 x 10.5 and dimensions 19.5 x 21.5 mm.
The stamp width of 19.5 mm and the vertical rubber break lines led me to the conclusion that it is Scott 637- rotary press with impressions placed sideways on the curved plates.
I have no information about the wide and horizontal line that appears on the rubber (I suspect that when the rubber breaks, there are pressure rollers that press on the cylinder with the role of keeping the sheet firmly stuck to the cylinder and leave a trace perpendicular to the breaking lines of the gum)
Is my assumption correct?
Is the position of these pressing rollers known? how many are? in which row/column of the sheet do they appear?
On the first stamp in the band there are some white dots and a break in the internal oval line.
Is it a plate error or just a printing error (dirty plate)?