I can't answer for the publisher, my copy is done by MPL and distributed by Hal Leonard. Mine does have the same cast and date info.
Honestly, the score didn't change very much at all from mid-May of 75 until it opened and since the only change was the addition of John Mineo as an u/s for a few of the male roles, it's not something that surprises me.
With regards to the revised "What I Did For Love." I have absolutely NO idea when that was ever used. I've only heard it performed once (by a college), every other time is the version we know. It's also worthwhile to point out that no recording of that has ever been made, live or studio, legal or bootleg. I don't know when they started using it (they say 1977, but again, no where have I seen this to be true) or even where.
http://www.youtube.com/huskcharmer