No -- in 2019 Google Ad Manager announced it was moving to a first-price auction (https://blog.google/products/admanager/simplifying-programma...) and AdSense followed in 2021 (https://support.google.com/adsense/answer/10858748?hl=en). (Edit: With regard to Google Ads for Search, they no longer seem to commit to any particular algorithm for deciding what price gets paid.)

There are some lawsuits that allege that Google was effectively cheating before then, by sort of manufacturing a shill bidder, with privileged access to everybody's bids, that turned it into something closer to a first-price auction (https://www.wired.com/story/google-antitrust-ad-market-lawsu...). The quotes from within Google look pretty bad, e.g. one Googler allegedly wrote: "Doesn’t that undermine the whole idea of second price auctions? I.e., the assurance that you can bid the maximum you’re willing to pay with no negative consequence. But if the publisher manufactures a floor based on your bid to get you to pay more than the second price, this principle gets violated. It’ll transform the system into a 1st price auction where the bidder has a strong incentive to bid LESS than he’s willing to pay. (Only just enough to win.) I don’t think that’s desirable for either side in the long term."

Google... disputes this (https://blog.google/outreach-initiatives/public-policy/ag-pa...). I guess we'll see.