G'day Ralphael,
I agree, also a SS may have colour around the borders
as opposed to the paper of the pane perforated.
As an entirety, they attract a differing catalogue number anyhow
"Sir F. A. Rien"
One would expect that, to extract the maximum revenue, Greenland would
have
made some difference between the 'singles' and the sheetlet. After all why
lose that $7.79 plus postage and handling!