Back in the old days, AM Radios had one less digit.
When I was growing up, the most popular station in New York City was 77, WABC. The station is still around today, but when you look at your radio it now reads 770, instead of 77. It's still the same station, broadcasting from the same frequency, but for whatever reason, radio makers have started showing the last digit, which is always zero.
As a tech guy, I'm aware that the radio display reflects the actual frequency of the station as measured in kHz, but since the stations are 10 kHz apart, the last digit is always zero, so there's absolutely no reason for it to be there.