If the claims of the child application are the same as the parent (or approximate the parent), the USPTO is likely to issue a double patenting (DP) rejection in the child case. To properly respond to that DP rejection, you would need to: a) amend the claims of the parent or child case such that they are patenably distinct; b) file a terminal disclaimer; or c) abandon the parent or the child application to remove the DP problem.
Since the inventorship of the parent application is screwed up, there is no point in maintaining the parent once the continuation application is filed (assuming that the inventorship cannot be corrected by amendment under 35 U.S.C. 116/37 C.F.R. 1.48 and there is no independent basis for maintaining the parent). In those circumstances, I would expressly abandon the parent to avoid the DP problem.
That being said, the specific answer to your question is "no, express abandonment of an earlier filed application is not "necessary" when a continuing application is filed to correct inventorship." Whether or not the earlier filed application could be ethically pursued when you know that the inventorship is incorrect is a different issue, but "express" abandonment is definitely not required.
Thanks Klav. I agree with your observations.
Remember to expressly abandon, you must get signatures from each inventor or a 373 assignee.
