It is possible to retain the safety lever when converting a standard S&W auto to DAO. I've even seen a conversion where a factory S&W DAO had the safety lever retro-fitted.
This may have changed, but you might check whether they are just removing the single-action option from your pistol (leaving you with your current long DA stroke only), or if they are installing the short-stroke DAO parts. From information and belief, they are only doing the former.
[This message has been edited by Daniel Watters (edited February 20, 1999).]