I am an architect and have been asked to advise on the replacement of existing door hardware with new electronic hardware. The existing doors and frames are HM, are rated for 3/4 hr, and have 1980 era mortise lockset sets. The current code requires 20 min rated doors. The Owner would like replace the existing locksets with an electric lockset, operated by either a card or a "fob" (similar to most hotel rooms). The new electronic locksets are rated for 3 hrs. The existing locksets include a 1 5/16" hole (at the corridor side of the door) for a key cylinder. When the existing locksets are removed, the hole for the key cylinder will be covered by the new hardware. However, the hole will not have been filled, it will only be covered by the (steel) face plate of the new hardware. Will this invalidate the rating of the door, preventing it being considered a 20 min door? There are a total of 140 doors, so replacing all of the doors would significantly increase the cost of the project.