Alvar Aalto Stool - Right Legs Wrong Seat?  

Is the seat marked at all?

I have 5 or 6 low stools with backs with the same exact seats (same vinyl and staples) in blue and yellow.  They came out of a school.  I always thought the vinyl was added, but now I wonder if it was an original option at some point.  I removed it from a couple and underneath there is an unfinished wood seat.  I have included a picture of the underneath where you can see the staples.

Hello
The underneath isn't marked.  There are no nail marks where a Finmar badge would have been and I've never seen an Artek mark on the stools made by them.  Very interesting that there have been some chairs with the same vinyl.  Is anyone aware of any other manufacturer ever having produced Aalto style stools and chairs with the Aalto solid birch wood leg construction or maybe this is another version of an Aalto stool and chair?
Many thanks for the comments so far
Sarah
 
 

Here is one that was for sale on the Artek website
 
http://2ndcycle.artek.fi/alvar-aalto/tuoli-67.html?___store=english&___f...

I have a catalog that shows this stool with upholstery as an option...
edit: in case the text is hard to read.  It says the model 60 comes with tops:
a). lacquered natural or colors
b). linolueum with a birch edge
c). upholstered

@ jesgord
If the seat diameter of your chairs is 37.5cm then I think my stools have a chair seat rather than a stool seat.  The 2 'stools' I have don't stack as the legs have been set too far in like on a chair.
I've looked carefully on the underneath of one and I can see original pencil marks for 4 legs which ties in with your chairs.  On the other there are some additional screw holes which look like they couldn't decide whether to make it a 4 leg chair or a 3 leg stool.
I've taken the legs off one stool and it's obvious from the patina that all of these additional screw holes etc were done at the factory and not a later adaption so I think I have a pair of original non stacking stools that have aspirations to be a chair!