I feel your pain.
I went through the same pain of trying to get a Jabo to be an Akro----many, many times.
This one is not an Akro—it is a Jabo imho---or a late Vitro—pretty much the same after Jabo purchased Vitro.
Jabo “Classics” do show up with cut-lines and they can sometimes fool the very best.
Get a feel for these Jabo types. The glass is just different; you can almost feel it with your eyes closed after awhile. They, (Jabo) made some very nice marbles—just not an Akro.
All opinions are welcomed and appreciated.
Marble—On!!