Wait, something's not right... you mean it was optional to get a front antenna OR a rear antenna? Whats standard with an AM radio then, NO antenna? I bet that reception was good.
I'll bet it was 61.10 for the front antenna AM radio, and an extra 9.50 for the rear antenna option... unless it was the other way around, and the AM radio option came standard with a rear antenna... but I always thought the rear mount was an extra cost option.