An interesting (but no more illuminating) addendum to the confusion--the Registry says that 1074 was rebuilt from M/10003, and that the whereabouts of M/10002 are unknown (or were as of 1997, at least). According to SAAC, 1075 was not a Mirage rebuild but rather was "built from new with Mirage-style modified front upper chassis". Who knows. The Registry also echoes Legate (or vice-versa) in stating that 1075 (and 1074) ran at various times with 289, 302, and 305 engines--
Sorry, Hersh. I need to fire up the time machine--
Bob