Yes - that is the way I have my PC setup. I hooked the Connect between my PC and my PC external speakers.
Not only can I then play my computer sound to any Sonos speaker in house (including the PC external speakers). I can also play Sonos music via my PC external speakers. My office PC shows as a Zone in the Sonos app.
Respect the Queue (2)Move (3)Beam (1) Era100 (2)ARC (1)SonosOne (1)Playbar (4)Play5 (4)Play1 (3)Play3 (1)Port (2)Connect (1) Roam (2) Ace (1)Connect:Amp (4)Sonos Amp (1)Sub + (9) Echo + Smartthings; (2)Play)