Alan Freeman started his show a lot sooner than that, 73 to my certain knowledge, possibly earlier.
It was particularly notable because it was available in FM Stereo using the Radio 2 channel, long before Radio 1 had its own FM channel.
In those days, Radio 2 provided sports coverage on Saturday afternoons on its AM frequencies (the radio equivalent of 'Grandstand' on TV), allowing the higher quality FM channels to be used more effectively for music. They did a similar thing during the week after 10pm for 'Sounds of the Seventies' - and of course on Sunday at 6pm for the Top 20 as it then was, with Tom Browne.
When I first heard it, the Alan Freeman show included a game segment, called 'The Name Game', where he gave the initials of song titles and you had to work out what the songs were. Can't recall if there were any prizes though. Two example questions I can remember - 'P O M M' and 'S I T S O L'.
Later on the game format changed to something else, which again I can't recall off hand.