Why? There were no numbered seats. Only the Main Stand had numbered seats at that stage.
I can’t see the point. Maine Road had a 63,000 capacity and the biggest attendance I can recall before promotion was for Huddersfield on New Years Day 1966 when 47,171 were there.
The first match I can ever recall buying a ticket for was the Everton Cup match in 1966. I remember them being sold in the turnstiles at Maine Road on a Sunday morning. After promotion, even the United matches were pay at the gate. I also bought tickets for the replay at Goodison Park and the second replay at Wolverhampton.
I was at all those cup games and iirc I have the programme for the game at Wolverhampton somewhere which is a one page team sheet.