Not really. Mercuria's shelve extension existed for a while but it only saw its way into Mercurial Core and made available by default with the release of Mercurial 5.1.
https://www.mercurial-scm.org/wiki/ShelveExtension
I feel it's disingenuous to clam that a feature was provided by an application if it's only provided as an add-on that requires the user to explicitly enable.
The standard way mercurial added new features was to gate them behind configs and only after they were widely tested turning them on by default. This is a good thing!
Prior to shelve being included with the mercurial distribution a third party extension was available going back to 1.x (or perhaps before I started using it around 1.8). And get this, it also prioritized ergonomics and was largely just adapted directly.
Would you consider it disingenuous to claim that there's visual UIs for git? It seems weird to ignore extensions that are extremely well known within the community. Plenty of people recommend using Firefox because it supports better ad-blocking extensions, even though those are also "sold separately".
But it’s a good example of why mercurial was better. It’s more ergonomic. All of the parameters on shelve match what you’d see on other hg commands and to shelve and unshelve you use those commands, not pop and push. You can also give short names to shelves for use in the ui, not just the message or sha.