I’ve been told the “bug eyes” were empty on planes with ALR-56, yes. And that carries with what BAE put in their old brochure image
The above contract just suggests the bug eyes are used for new digital ALR-69A, where planes with non-digital ALR-69 have received Antenna Optimization modifications. I don’t know what the AO modifications were, so don’t have info on the current layout of antennas on aircraft with ALR-69, or ALR-69A to say whether both the beer cans and bug eyes are used simultaneously or not.
I only know that beer cans were first fitted in the middle of Block 30 production around the time the delayed ALR-74 RWR originally intended for F-16C, wasn’t working out and decision was made to pursue ALR-56M. The beer cans were retrofitted on older airframes including Block 25s. So either those are present on planes with either legacy RWR system as a full replacement for the bug eye antennas, or they are supplemental antennas on F-16s with pre-digital ALR-39.
