Eames arm shells with 3 dots and an AX logo/ stamp  

You are correct. Probabaly a Summit Plastics, Kalamazoo MI shell from around 1954-56 ish.
I'm a little blurry on the sigificance of the "AX" stamp, but I believe there was a Fritz Hansen Designs distributorship or "collection" of some kind for a short time (I think in the USA, but not sure.) 
I have a pair of shells with eiffel bases from a Baltimore, Maryland estate with the three dots and the AX stamp. The seller swore they were purchased new by the original owner in 1954-55. The glides on the bases are original boot type, and the color of the shells (a very pinky and opaque salmon) seems to support the seller's dating.
Hope this helps!

I have the same chair, thee dots and stamped AX. 15 1/2 inches tall, and no round things on the bottom of the legs.
Is this chair valuable?

Sorry, I guess someone has to say it… "this is not a valuation thread"
3rd (last) Zenith generation, 3-dot Zenith 1954-55 ish…
a very desirable color ( Elephant Hide Grey )
really nice beautiful chair, fairly early, uncommon, but not ultra super-duper rare.
the AX stamp is cool, and adds mystery, but probably doesn't change price (yet)
I have seen these transitional shells with both early x bases and later H bases.
also some with early large shock mounts, but most with smaller shock mounts such as yours.
this is probably a first version H base that happens to be missing its boot glides. early boot glide type H bases were only made for a year or two
there are plenty of completed auctions of these on ebay for comparison
age matters
condition matters
color matters
fiber beauty matters
patience in selling matters
with a name like "Fliper", I guess that says everything?
(was the above a valuation?)