Assuming the aluminum castings on the Holz-her are the same as the AEG version then the answer is YES.
I have installed a new Festool sanding frame and end fittings on an AEG sander and it fits just like it should.
I can even swap the new frame for an old AEG sanding frame and the fit is the same.
The key is in the factory pre-adjusted end fittings which arrive ready to mate/compensate the odd angles of the sander casting
so that the bottom of the frame is coplanar with the belt platen.
The new frame has one improvement in the casting. It’s thicker and taller at the place where a maladjusted belt will try to grind through the frame.
The new frame only has a paint finish but the fasteners are updated to Torx from Pozi.
The end fittings are a bit of a pain to install, especially the front piece, but they have included different fasteners for the rear piece which makes it easier to install than the old version. Both ends use 4mm socket screws. The front piece is tricky to install but will be a lot easier to instal with a 4mm screwdriver style tool rather than a L wrench. 5/32” works too. This is one piece that is not as good as the old. The new binding plate the screws thread into is smaller than the old style so it’s hard to hold it in place while driving the screws. The spring clip that keeps the sander engaged with the depth adjuster is different, not sure I like it but it works.
When setting the sander into the frame the first time you’ll probably need to loosen (T25 tool) two of the black nylon pylons (one front and one back) that key into the grooves in the sander casting. I found them too close together to seat the sander. And once in they were still too tight for the sander to move up and down smoothly when the quick release depth adjustment lever is moved.