From my experience, it is.
I recently called to see if I could get a retention offer on my AmEx Bonvoy Brilliant, but they did not have any offers for me.
They did offer a downgrade to the card with the $95 annual fee, but I kept the Bonvoy Brilliant.
Edit: I also upgraded last year (March 2019) from the $95 SPG card to the Bonvoy Brilliant for an upgrade offer similar to yours.
Last edited by TheIronWill; Apr 20, 20 at 8:17 am