Actually the only "untitled" Zeppelin album was known as 4 or Zoso so it wasn't actually a self titled album like their 1st album. They were going for the mystique factor and it worked.
I knew PG had an album they called PG2 or Scratch as it was referred to but didn't know he did more than that.
I know Heart did it as a ploy in 1990 trying to reinvent themselves but someone else did it before them and restarted the trend. I just can't remember who. I know Heart bragged about using it as a ploy in their behind the music show and they credited the record company.
In this case with KSE it makes zero sense to me.
7/30 - Offspring
8/4 - Soundgarden & NIN
9/27 - Clutch
10/24 - Judas Priest & Steel Panther