Rockford runs after a masked gang of kidnappers and takes a shot at them. His bullet strikes and dislodges the left-front hubcap of their awaiting vehicle. As they drive off, the hubcap can be clearly seen on the left-front tire, from which it had fallen.
The oil depletion allowance is a tax deduction (a kind of depreciation), not something that an oil company has to pay out in cash.
Police officers are parked at Jim's trailer waiting for him. After the officer exits his car bystanders watching the filming are visible in his side view mirror.