[Mr70]

Tony that's very possible,not every car was factory assembled with a radio,and definitely not the norm.
1970 vehicles equipped with factory radios had their antennas embedded in the windshield,not the fender,so check the windshield,not the fender.

Also,check to see if you have a factory dash speaker or mount still.
And see if you have tinted glass or clear glass,because beginning in 1970:
When no Radio was ordered,and Tinted glass wasn't either,the clear windshield will not have an internal antenna lead attached to it.

When no Radio was ordered,but Tinted glass was,the tinted windshield will have an internal antenna lead attached to it.

When a Radio was ordered,but Tinted glass wasn't,the clear windshield will have the internal antenna attached to it.

When a Radio was ordered and Tinted glass was too,the Tinted windshield will have the internal antenna attached to it.