No, 'Hole in One' was the first planned episode of series 4, and just one day of location filming had been completed (the scene outside the court after the hearing, plus the scene outside the Nag's Head at the beginning of the episode) before Lennard was taken ill. When Lennard died and Buster came in, John re-wrote the episode for Uncle Albert, as well as two brand new episodes, 'Happy Returns' (as they didn't want to start the series with the funeral episode, so 'Grandad' was said to be in hospital, though Lennard had sadly died), and 'Strained Relations' (where Grandad was buried and we met Albert).
Some footage from Lennard's appearance in 'Hole in One' actually remains in the episode. It is in the scene outside the Nags Head, where Albert asks Mike "How's that deep-fat fryer Del sold you?". This had been shot once with Lennard, then re-shot a month later with Buster. However, the shot of Kenneth MacDonald replying as Mike was taken from the original footage, and it is the edge of Grandad's coat we see in the corner of shot, not Albert's.