I think the fear was that subjecting a PCB to the vibrational stresses imposed during launch could possibly crack traces or solder joints. Even with P2P, they spotwelded where they could. Whatever the reasons, the equipment proved to be reliable. I don't think there was a single comms failure across the entire program.
Well there was the famous SCE->AUX comm failure, but that wasn't due to the construction of the modules.
They had printed circuit boards back then but point-to-point wiring was very popular.