Is your antenna an original stock part, Joe?
If we’re talking stock rear fender placement on a ’69 Camaro - mine measures 14 inches from center of antenna hole to back edge of fender - and a stock rear antenna - at just under 20 inches tall when fully retracted, (available for AM radio only) it will be too tall, even in the down position, to miss either spoiler available that year. A front antenna was required with a spoiler equipped car for ’68 & ’69.