The 16.4.2 sold with ears included so the ears never sold as a separate item I guess.

Probably the fastest way to a pair of ears now is find a metalworker and show him your mixer, the Mechanical Drawing and the Rack Ear Installation Instructions. Note that the screws used are countersunk metric type.

Another option would be to make a set yourself. Its just a piece of angle iron whit holes drilled into it. You can get angle iron from Home depot. Just measure how high you need it and make sure the thickness is not any thicker than the brackets you are taking off. The mechanical drawings didn't really show that.
Here is an example of what you can get. Just cut it to length. You might have to drill a few hols but that would be about it.


Key words to search for is slotted offset angle iron

The original rack ears are 1/16” steel, heavier than the brackets. The set comes with 8 slightly longer (6mm M3) screws to replace 4 side panel screws each side of the mixer.

SwitchBack wroteThe original rack ears are 1/16” steel, heavier than the brackets, so the set comes with slightly longer (6mm M3) screws.

You now know how thick the metal has to be and the length and type of screws. The easiest option is to get a set made but if you are on a budget, you can get away with making them yourself.

They seem to be available, after all those years...

https://shop.presonus.com/1642-and-CS18 ... unting-Kit