If the radio really is NIB and has no mileage on it, you probably won't have electrolytic caps fail until you put a few miles on it.
The stock setup on that radio is for the transmit frequency to be "fixed", set by a small trimmer pot and another small trimmer capacitor inside. The front-panel fine-tune control is only active in receive mode. The FCC made this a requirement around 1974.
To participate in a round table with more than one station, it's very handy for everyone to transmit on the same frequency. Kinda hard to do with radios that have this stock setup, since the setting of that trimpot inside the radio will never be exactly the same for all the radios on the channel.
This makes "cutting loose" the front-panel clarifier a popular modification. This way, everyone is transmitting on the same frequency that you're receiving.
So long as there are only two stations in the conversation, there is no reason to do this. They can tune each other in just fine. But as soon as that third station comes on the channel. he has to choose which one to clarify, or twist the knob every time a different station keys up.
The conversion is not a big deal.
Just the same, it's also possible that the radio's internal frequency settings for each separate mode have drifted since the radio was built.
This is the bugaboo of sideband. Fine tuning is critical to get clear audio.
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