Miscellaneous Thoughts
Cynics will disagree, but for someone like me (who cries at most episodes of Star Trek Voyager) it IS a moving story - though to some extent it rips-off "Shadowlands" (a far greater movie - partly because it's a true story and partly because Anthony Hopkins and Debra Winger are way ahead of anyone in this picture).
LDS is not particularly prominent in the movie. In fact, I don't think the work "Mormon" is mentioned even once - it's more conspicuous by its absence. Apart from the baptism (which not many non-Mormons would recognize as being specifically LDS) only two scenes spring to mind: The first is where Sam takes Charly to church, and we glimpse two beautifully turned-out young women with suitably blurred name-badges welcoming people into the building. The second is when we see "Study Guide 1" together with what looks suspiciously like the "Book of Mormon" on Charly's nightstand. People unacquainted with the LDS church would not read anything into these, and assume that what Charly is converted to is just regular (most likely protestant) Christianity - though they might of course be reminded of the movie when they encounter Mormonism in real life.
However, I can't agree with the other extreme view: namely that the movie is aimed PURELY at LDS members. If this was true, I feel sure there would have been a Temple marriage ceremony in the movie - or at least some mention of it. I *know* how important that is to LDS people: I remember many years ago sitting at the back of an LDS chapel, listening to a young girl on-stage blubbing and sobbing as she told about her and her fiance's upcoming trip to the London temple. The tagline "Real Love Stories have No Ending" and even the closing "Not The End" imply that's what Charly and Sam's marriage was about. And we see and and hear nothing at all of any temple ceremony. In fact, we don't even see Charly receiving her Endowment, but of course I'm no expert on LDS rites: Perhaps someone in Charly's would not have been considered ready for these ordinances, and they would eventually have been performed on her behalf after her death. (Maybe there's someone reading this who's more learned in LDS tradition who could answer this.)
P.S. I don't think it's any answer to say that Endowment and Celestial Marriage are closed ceremonies. I don't imagine that LDS authorities allow film-crews into temples, but I *do* think that in real life the fact of *going* to the temple would be spoken of. The fact that it isn't suggests a tip-toeing around certain aspects of Mormonism for the benefit of non-Mormons.
P.P.S. Another thought - I've only ever seen this movie on British TV, so maybe it was Bowdlerised for UK audiences. Does anyone remember more LDS-references in the version *they* saw?
P.P.P.S. Just looked at some clips on UTUBE. Previous theory correct. Definitely LDS-bits in there I don't remember seeing on TV.