IMHO it makes no sense to use an opamp which has its own offset issues (NE5532) due to lo input impedance and thus high offset current in a servo which is commonly designed with relatively high impedance parts.
You _can_ use a NE5532 as DC servo as long as the servo reduces the original offset which can be some if the amp was discrete. You can get much less than 10 mV from a NE5532 that may be OK in many situations.
