Yes, some of the changes in the TV adaptation are taken from the two prequels ("Prelude to Foundation" and "Forward the Foundation"), but with some significant differences.
- The robot assistant to the Emperor-Triad is adapted from the prequels. In those books, the name is "Eto Demerzel" (at least, to the Emperor, that's how it's known).
However, in the books, the Emperor does not know it's a robot (actually, it's R. Daneel Olivaw, as the young Hari Seldon eventually works out – the only person ever to do so).
- Raych is also a character in the prequels: A young (orphan?) ruffian from the Heat Sinks who is adopted by Hari Seldon.
However, in the books, Raych is no longer around by the time of the Exile to Terminus (but his daughter – Hari's granddaughter, Wanda Seldon – becomes an important player in the establishment of the Second Foundation).
- The various religious groups – such as that on Synnax (Gaal Dornick's home-world) and the Luminist Faith (with its bald, female Zephyrs) – may be very loosely based on the Mycogenians of Trantor in the prequels – an isolationist, ritually depilated tribe, with no real love of (or loyalty towards) the Empire/Emperor.