Unsure of stamp identification
Is it possible for US
to have upper and lower straight edges and vert. perfs 11?
edited September 12
Can you post a photo of what your are trying to describe? That stamp is an 11 x 10 1/2; the horizontal is perf 11, the vertical is 10 1/2. It is not a 634A that you are describing, but sounds like a coil stamp? Also be dead-on accurate with your perf measurements.
I think what you are referring to is a coil stamp... and yes, the A157 design does appear on coil as a 599A (Type II).
Value of the coil is lower than the 11 x 101/2 perforation.
599A (CV for MNH is $200, OG $100, Used $16) while 634A is (MNH $600, OG $300 Used $13.50)