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fkwD350-1 and Gimbels yes, they are 1916 M101-4/5 group.
D350-2 and Boston Store no, they are 1917 E135 group.
The most common of the M101-4/5 group are the blank backed cards.
There are 20 different backs found in the M101-4/5 group (not including variations).
I think Leon had a list the M101-4/5 group broken down from common to rare, I'll see if I can find it.
Here is a link to a post from a couple years ago thats shows roughly the multipliers of scarcity.
http://www.network54.com/Forum/153652/message/1088625773/