That\'s possible...
You can go with AC140 even if I-824 is approved. Infact, I sent my I-824 approval notice (in addition to I-824 receipt) along with my AC140 case. My case has been created at Mumbai.
All you have to check for is whether a particular consulate is still accepting AC140 case.
The whole purpose - and Mumbai\'s US consulate\'s management commendably understands it - of AC140 is to finish off the GC process faster. I-824 route to NVC still takes longer and hence consulates, if load permits, do not mind accepting it. Mumbai consulate is really customer friendly in this respect.
And even if the consulate doesn\'t accept your AC140 case, you still have the usual route through NVC. So no harm. I was skeptical about the whole AC140 deal (since Chennai had stopped doing it) but then I-824 approval restored my confidence.