In a word, no...
Stock Radio? No, Strapped Radio? Perhaps...
The only real way to check, is to VERIFY that the SHIELD of the COAX is to the SAME as FOIL Ground - back at the Negative side of the Power connector.
You can also VERIFY Ground - between the Power Connector Negative and the LUGS mounted on the Heat sink.
Anything above 1 ohm - no...can't use it for ground...
View attachment 36421
When you do a continuity check on the back panels Negative Power lead to CASE - and it shows open - then you know...No.
Correct foil ground/board ground that the final mounts to (yes I know it’s insulated from ground)
I ran a circuit under the board through a slot and used circuit board ground
I’m having a short to ground somewhere intermittently internal of the amp I been chasing down checking caps and diodes nothing yet