Yes, the release dates you see above are accurate to the dates displayed in-game. 
Version 26.1 has recently been released as one of the biggest updates in Infinite Flight history, with few things remaining as they were presviously. Among the many changes, we received a brand-new aircraft selection UI. After several trials during the Open Beta for 26.1, the final result is what we currently have in-game. One of my main criticisms for the final design is the lack of aircraft release dates (or, at least, their removal via an easy and convenient access).
They are still accessible, however only if you have a flight on Autopilot+. On the AP+ page, you can click on your aircraft as if you would change it. That will take you to a different submenu, which will say the release date of the aircraft you’re flying. Not particularly convenient. On the new aircraft selection grid, there’s quite a lot of empty space below each aircraft preview, space, which, in my opinion, would be perfect for displaying each aircraft’s release date, as I’ve depicted above.
I suspect a reason for their removal is that sometimes they’re simply not correct. The 737 MAX, for example, has an in-game release date of October 2024, despite not being released to the public until December 2024. Another potential reason is that they can be rather misleading in some cases. The A320 family is stated to have a release date of November 2015 (December 2015 for the A321). The whole family received an important update in August 2019, featuring live cockpits, and that information wasn’t accounted for on the release dates. However, the 737NG family predates the A320 family by over a year, being released in February 2014 (May 2014 for the -900). Like the A320s, the 737NGs were updated with live cockpits in June 2020. Unlike the A320s, however, the 737NGs are stated to have a release date of June 2020. Perhaps a better criteria for these could eventually be developed.
