I have an at-least 15-year-old (iron) Lee Classic "O" press. I am having a push-through sizing die made that may need larger dies than standard. Lee's web page on the Classic "O" press includes the following: "The original Classic Cast designed to work with large series 1 1/4-12 dies. Includes breech lock quick change adapter and breech lock bushing to accept standard 7/8-14 dies."
To the best of my knowledge, the press has not changed. What has occurred and remains ongoing is the Class "O" adds features by way of adapters of all sorts. But I cannot verify is whether my old version accepts Lee's adapter for using larger dies.