[QRO] ssb refresher course needed

[rb]

I need a brief refresher course in HF SSB.  It's been awhile now since I've
been into this stuff....

Assuming a modern, commercially produced SSB final amp is operating in
linear mode, is not overdriven by audio or rf gain on the input side, and is
not distorting, can the transmitted signal still be wider than the 3khz
standard?

Based on the above conditions, if an amp is putting out a SSB signal that is
too wide, what practical means are there to narrow the sideband down?