As far as I can remember, the Mocat designation for all the cb radios, antennas, and accessories except the in-dash stereo units. Motorola was still big into aftermarket AM/FM car stereos at that time. The 4009 model number was marked as Motorola and not Mocat. It was supposed to have a second receiver just for channel 9 monitoring. I think it had a button to activate the receiver, and did have a second squelch control. I don't know this to be true, but I think they was marketed thru the Motorola LMR shops in order to bid on contracts for state and local police radio sales. The 2000 series were 23 channel radios, and the 4000 series were 40 channels. I've never seen any documentation on decoding the serial number for the manufacture date. I think I saw somewhere on the net years ago that they actually manufactured by a third party. They were pretty good radios, but were expensive, and not as easily peaked and tuned, or adding power mics and such. I did have a 4009 that I got off of ebay, but it was pretty well beat up and did not receive.