Heya Brettt777,
When you're asking about a building editor are you asking about GMAX? GMAX is a program that was included in FS 2002 Pro that you could build 3-D models of aircraft and scenery with. Once finished with the 3-D model you could then import it into FS 2002.
If this is what you are asking (sorry but your question is vague) then the answer is no, it is not included in FS 2004.
Don't despair! A freeware (new and updated) version of GMAX came out about a year ago and is available for download here:
http://www4.discreet.com/gmax/I hope that this answers your question. If your question was referring to something else please explain further.