I have seen the same used on discrete power amps with a thick and "spongy" thermal pad on the bar to even out the differences in thickness. Then it was possible to clamp e.g. both Sanken MT200 power transistors and TO-220 VAS transistors with the same bar.
I would think that's fine. It also puts the clamping force directly on the body of the device and not on the flange, so there should be less risk of having devices that aren't completely flat against the heat sink (which would lead to thermal instability).
^When you held it, did it "spark joy in you"? Edit: now on Netflix! You might want to consider "Döstädning", next https://www.washingtonpost.com/lifestyle/home/americans-are-pack-rats-swedes-have-the-solution-death-cleaning/2017/10/12/248dcf82-aebe-11e7-a908-a3470754bbb9_story.html https://www.telegraph.co.uk/women/life/dostadning-scandi-lifestyle-trend-anyone-knows-hoarder/ https://books.google.com/books/about/The_Gentle_Art_of_Swedish_Death_Cleaning.html?id=glX2twEACAAJ&source=kp_book_description
http://www.synthtopia.com/content/2019/01/06/arp-founder-alan-r-pearlman-has-died/
RIP Alan R. Pearlman, the man behind the ARP synthesizer company which made some excellent products and had many, ahem, questionable business practices. The ARP 2500 and 2600 are the stuff of legend.
http://www.vintagesynth.com/arp/2500.php
http://www.vintagesynth.com/arp/arp.php