User blog comment:GeorgePowell/If I chose to continue playing on ME2, am I able to transfer my file to ME 3/@comment-1221773-20110706174624/@comment-774818-20110712181741

It probably will depend on which save you use. If say save #30 is the one you first saved after beating the game, and in #32 you beat LotSB, if you import #32, it will "recognize" that you beat LotSB. My guess is that any save made after destroying the collector's base will be viable for import inot ME3, just as they are viable for import into ME2 again.