Question about integrated amp hookup

Greetings. Excuse my ignorance but the back of my Creek 4330 Mark 2 from 2002 has a separate RCA connection that is identified as “Pre amp output/ power amp input.” Does that mean that I can connect a more powerful amplifier to the unit and then basically use it as a preamp? The Creek has 45 watts per channel and sometimes I wish I had a little more power. Thus I was thinking about adding a classic old amplifier.  I like the Creek for my second system in which I use a turntable and CD player—I added a phono board. In the manual they say they also have an optional “gain stage module”. Does that mean that I would not have to turn the volume knob that high if thus equipped? Thanks.