It mostly depends on the museum (public or private). Each museum and private individuals have different requirements for copies. Some are very helpful and some can not disseminate proprietary information by their bylaws and licensing agreements (which should be respected). There are many options and other avenues for making a reproduction of certain owned pieces. Are there other pieces available made by the original cabinetmaker or shop which can be copied. Change a primary aspect of the piece. I have always thought that if a museum has the capability to sue you for an EXACT reproduction then you must be doing something to wright about. Change something or try to build the same piece in a parallel universe.