For what it's worth, my 4000PC-50 (4340/A) has an identical passel of
chips but with a different (suspected) I/O ASIC and memory controller
logic.

Here's what's silk-screened onto the suspected I/O ASIC:

LSI Logic
L1A7528
(C) MIPS 1992
32-00099
R4230
NAS 9250
WF36415 JAPAN

Here's what's silk-screened onto both memory controllers:

LSI Logic
L1A6092
MCT-DP V1
ARC 2
NAR 9215
WGE5722 GERMANY