Hi,
"As per my understanding , once we define External QM Systems attributes and installations then it ECC inspection lot is activated at client level ."
No. Well, you need an to define this. But you activate the Inspection Object Type (in this case 4) for each warehouse. If you do not enter there an external system, the inspection is only based on the QIE inspection rule. If you enter the external system, you still have a QIE inspection rule, but the system will call the ERP system to create the inspection doc there, but also the material master in ERP needs an inspection rule setting.
So from my gut feeling I would say - no, it is not possible. But have you ever tried it? I did not yet, I have no idea what happens if the QIE sends a message to ERP and there is no inspection setting for the material there. And if the settings in the QIE inspection rule (which are usually not used with the external system) are then beeing considered. I would recommend to try.
Brgds
Juergen