The flange isn't quite flat, and I have to cover/seal around the hole for the old external wastegate. It is possible though unlikely, that a chunk could get into the turbo housing and get blown through the exhaust wheel. EEEK.
Better safe then sorry.
Thanks guys - Evan
EDIT, after much searching I have given up on finding a gasket. Seems to me that the RTV is the only way to go, especially if getting another gasket is this big of a pain.