Hello! Let me start by saying I two, (lol) have one of these radios. It has some issues and poor channel modification attempts where the wiring on the switches has been miscombobulated.
So after about 2 months of doing research on this radio, I have found the board they used in this model, I have been able to tie it back to the Midland 79-893 mobile. The only thing that I can see that isn't there, is the SWR board. And they used a tone high and low switch on the mobile which the Teaberry Stalker Two (40 channel) didn't use.
I am certain this Uniden board that was used in this Midland mobile model is correct because it also is stamped like the one in the Teaberry Two base, which are same numbers in the center of the board PC-189AB.
CBtricks.com has this mobile on their website with schematics, parts layouts, wiring layouts, and block diagrams. There are also clarifier, and channel modifications available for this radio in other areas of their website I believe.
I hope this helps as well as solves the mystery for everyone who has one of these oddball radios.
Thanks!