Which DEC machine made use of th pre Flip-Chip board?

After groveling through the 'PDP-7 Maintainence Manual' (F-77A), this seems to be accurate. In "Module Identification" (pg. 6-5), it refers to both types; the example on the next page uses a 4303, a 4000-Series System Module. What's interesting is the physical layout; all System Modules at the top of that image, and FLIP CHIPs at the bottom. No doubt this is partially for mechanical reasons (the two used different backplanes), but I wonder about the division into sub-systems; were the two types interspersed among each other in individual sub-systems (rewquiring running wires from the top to the bottom), or were sub-systems exclusively one or the other (so that the top of the bay is one sub-system, and the bottom another)? No doubt I could answer this by studying the prints, but time is short; perhaps someone who worked on the one at the LCM and already knows the answer can enlighten us! Noel