Looking at some pictures online, with the controls on the back, it doesn't seem like they'd have made one with an holder.
The hot-shoe idea still sounds good. You could also put a sticker on the window, as that'd likely not hurt the finish.
I saw white electricians tape at a big-box hardware store yesterday. A piece of this on the base plate or the back of the camera should do nicely, and it doesn't leave a sticky residue.
Much easier,cheaper and cleaner solution?
Yep, just cut the holder of a dead camera, glue to the back of a live one.
Done it about 5 times to various cameras.
For the expense and fuss of it, many alternatives costing little to nothing exist.
There are some great suggestions here. I like the folded up box end and slip into flash shoe. But a lot of MF cameras don't have a flash shoe...
Insert box top folded into a plastic keyring, attached to the strap (see pic). I have used this method on all my cameras for many years.
Or write the film and reference details on a strip of masking tape and place that across the back cover (covering the release latch), as most professionals do.
Those Hama box top holders can give grief. The longer you have one of these attached to the camera, the more aggressive the adhesive will be. I have known the leatherette of camera backs to be ripped off by forcefully leveraging the memo holder off. The correct method is to use a thin length of piano wire (or fishing line) and see-saw back and forth through the adhesive, then rub the remainder off with thumb. It may still leave a residual mark.