Did radio delete trucks not come with an engine grounding strap?

[Mister-B]

My truck is a radio delete. I've since purchased a factory AM radio, wiring, antenna, and factory speaker. It all works, but reception goes way downhill when the engine starts and especially when driven. Someone mentioned a grounding strap would help, if mine were removed or got rusted. Well, I couldn't see one on my truck. I went to the junk yard, and found two 67-72's with decent engine ground straps, so I bought them. I get home to install them, and I can't find the mounting hole on my firewall. It should be just to the right of the heater box on the firewall. I mean, I just removed two of them, so I know where to look... But I'm not seeing the hole in my firewall. Did radio delete trucks not come with the strap? Any other ideas of where it would mount?
Posted via Mobile Device