Recenter them on the servo wheel splines.
And sure you can use them on PCM...the PCM/PPM bits get sorted out before the servo...
And don't trash them old Gold radios....mine all met the narrow band requirements, it was the RX's that got replaced. I don't think you can still get a Gold Sticker on them....just not sure what the rule is on them now. Mine still work at my field
but I don't take them on the road...