That's before 1972 then. First time the Imps used two subs in a competitive game was for the Watney Cup match against Burnley in July 1972, presumably 12 and 14.
Slightly off topic but I seem to remember a player joining us and going straight into the team. I recall the number on his shirt was crudely drawn on with a black marker pen. Could it have been David Magic Johnson?
Well at first glance the use of high numbers does seem to coincide with success on the pitch. There appears to be a link to either mediocrity or crapness.