Will the Old Approved i-140 be Valid?

I already have i-140 (approved more than 180 days) with prev-to-prev employer.

If I initiate a new PERM and i140 is filled and Approved with current employer. Will the old i140 with prev employer is also good in case if we want to join back old employer in future and file adj of status with the old i-140 approved earlier with prev employer.
(Basically do we have choice of selecting between two approved i-140 with different employers to file adj of status if PD become current?)

In my understanding both i-140 are valid as both are different petitions with different employer so both should hold Valid and Good, please help me with your pointers.