I ended up being impatient and I got out the multimeter. A quick continuity test seemed to indicate that a larger resistor (D2?) directly beside C177 was in circuit with both of pads on C177, so I just soldered the power capacitor to the contacts on the resistor.
The card seems to work... Would it work if I soldered the cap to the wrong circuit? ( really showing my ignorance here)
I am, however, getting a bit of noise and the right channel is cutting in and out. This did not happen after I replaced the OpAmp (sounded perfect then). Could this be a function of a bad connection on the decoupling caps for the opAmp? (seems likely, as issue only occurs on line out connected to the opAmp/decoupling caps I replaced..)