There were at least two comments on piecing together/reconstructing a map. The site I linked to above points out
Printed sheets of map stamps had 12 rows of 19 stamps, for 228 stamps per sheet. This unusual format was to make good use of the total size of map sheets.
And if I'm reading the information correctly, there are 78 different, known maps used. That makes almost 18,000 possible positions for any given stamp.