Yes they are. Despite the PS5 Pro being taller than the PS5 Slim, the width and depth of the two consoles are exactly the same. The three lines that separate the top and bottom plates on the PS5 Pro have been added specifically to make the face plates / console covers compatible.
The official PS5 Slim console covers start from £44.99 and are currently available in a range of limited colours from PlayStation Direct. Each cover comes with 5 parts, including a panel for the optional disc drive.
Note that the original PS5’s console covers are NOT compatible with either the PS5 Slim or the PS5 Pro, since the original PS5 cover comes in only 2 parts (front and back panels).