yeah, that's the first version of the underhood cases that i know of...

first used on the 1227727 ECMs, then the 7727 derivatives in 90(1228708(?), the vette ZR1 PCM and W-body 3800)) and 91(16149396) and 92(92-93 LT1 PCM).... they all look pretty much identical externally.

then in 93, the second underhood style came around, which in 94 the LT1 picked up and was used for a few years until the dual 80 pin OBD2 underhood cases were used everywhere.