You got the mids!?
I do, although they're technically the same as the high's, they were just named Midlites until the late '90s.
At what point did they go from six hole baseplate back to only four holes?
To my knowledge, they surprisingly kept the 6 hole pattern until 2001ish, I can't confirm that 100% but after lots of extensive searching through ads & catalogs, it's what I'm fairly certain of.
I actually have a set or two from when they made the switch, and the casting was pretty sloppy on them.
I'm glad to see there's some interest in the trucks & the history! I'll try and go through some boxes and find everything sometime this month and get everything uploaded here.