The remaining rivets serve only to fasten the perforated rear panel to the rear edges of the sheet-metal cover. The cover is held in place by four bronze #8-32 machine screws.
The molex socket was the original design boo-boo. Would overheat and fail. Big time. The Mark IV was developed as a 23-channel radio, but the development process kept running into design snags. Took forever to coax their zillion-chip PLL and electronic channel selector to actually work. Most of the time. Ever ask yourself why a CB transmitter would need a knob marked "Reset" on the front panel? By this time the FCC had announced no more 23-channel models would receive "type acceptance" approval for legal sale, only new 40-channel radios would be approved. This sent Browning back to the drawing board to adapt the radio to 40 channels. This proved to be a tortured process because the technical performance requirements were stiffened for 40 channel radios. A 23-channel CB had no specified limit on how much RF garbage it was allowed to spew in receive mode. 40-channel rules set a fairly low limit. Never mind what happens when you key the mike. Can't leak any more than it does on receive from the power cord, external speaker/PA cord, mike cord, headphone cord, etc. The redesigned Mark IV had more issues than National Geographic. By the time they redesigned it as the "IVA" they had a decent radio. But avoid the mark IV like monkey plague.
The Molex socket was upgraded to the larger "Jones" connector just before the change from "IV" to "IVA".
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