Ah! I presume the 1932 or 1936 "Landscapes"
Yep, there are oooodlies of these common definitives.
They all look the same, but a colleague of mine who collects
switzerland, fly specks these, and just one stamp
with a flaw can raise 500 euros.
Do you store them all, just in case? ...Your call

dedicated catalogues will show the emmissions printed,
I have them for the US.