Yes. Sort of.
I understand that stashes are special hashes, but my point was more that the OP was making use of a facility that gives the behaviour of a hash, not the underlying mechanism.
However, I disagree with your argument. You only use what you are requiring to be exposed to you. A simple variable lookup does not necessarily imply hash use from a user perspective. There's a layer of abstraction present. This abstraction can be done independent of the hash implementation. Just look at how lexicals work.
Only when you the user takes away the layer of abstraction shielding the hash lookup does it become use from the users perspective. That is what has occurred here, therefore it is using a stash as a hash.