Whirlpool!
Here is the easy way of knowing who built the machine!
KitchenAid by Hobart used the simpler model designations like KDS and KDM.
The data plate would also have said Kitchenaid Division of Hobart Corporation, Troy, Ohio.
Your machine is a Hobart design built by Whirlpool(probably by ISE but that's another story) And it uses the Whirlpool designation of K"UD" signifying Kitchenaid Undercounter Dishwasher. Your data plate should read, Kitchenaid, St. Joseph, MO.
They still use the same system today.
It is nearly identical to the Hobart design and Whirlpool kept the same tank design thru the 23 series but with changes in some smaller details of the tanks in the 23's. The major difference came on the 23 series with the change to the Whirlpool Power Module pump system. The hole in the tank sump is smaller on the 23's so you can't swap out the pumps but many of the other mechanical parts will swap out.
My Monterrey is a Hobart built machine and is especially quiet compared to any other Hobart machine I ever had because the whole tank, top sides, back and bottom is covered with a layer of bituminous rubber as well as an addtional layer of foil covered fiberglass. The rubber coating really tanks the "ring" out of the steel as the water hits the inner walls. I have a Whirlpool built Superba 22 that only has the rubber halfway up the sides and back and across the top and it is noticeably noisier. I would like to know what they did on your unit.
You will love the Monterrey,so start collecting spare parts like racks and pump parts while there are still many of them around as most parts are no longer available and you can get lots of help from everyone on here too.