Personally, I think it makes for bad policy to have the tags be inconsistent.
Giving out the tag to the first film version that gets a question is arbitrary and tends to bias towards newer versions of the films. I feel this can end up being confusing... because it confused me when I started looking into this situation.
If we want to say: The older (or newer) version always gets the generic tag, regardless of the popularity of the films, that's at least consistent... I don't particularly like it because (in the case the older gets the generic) there are potentially times when the older version is obscure to the point of being unknown or (in the case of newer getting the generic tag) the older version is a classic that deserves the generic but... at least it's consistent.
I think that, if there are two films (or TV shows) with the same title, they should both (or all) have dates on the tags. This does a few things:
Simplifies tagging for non-veteran site visitors... they're unlikely to use the wrong tag if neither tag is generic... and, lets be honest, they probably don't always read the tag wiki to make sure... but the dates make the wiki less necessary.
Clarifies exactly which film is being discussed. A film generically tagged godzilla could potentially be about any of the films and, if the OP doesn't make it clear in the question, answers can be wrong. This is particularly the case with films or TV shows that haven't been asked about yet and don't have tags, as was the case with the cinderella tag. At different points in time (and by different people) it was awarded the cinderella and the cinderella-2015 depending on which film people thought the question was about... despite the generic tag never existing before.
Honestly, I think that all film tags should include dates regardless of if there's multiple versions of the film. Yes, it makes the tags longer but it leaves zero doubt about which film is being discussed. Doing this prevents the tags from getting changed in the future (because apparently this is an issue?) and it also sets the film tags apart from other tags.
In the case of a TV show and film having the same title, I feel like adding a -tv to the show title and the date to the film title is probably the best option. This doesn't happen that often.
And seriously this should be fixed:
lord-of-the-rings:
Movies/television about the epic work of J.R.R. Tolkien. Usually refers to award-winning trilogy by Peter Jackson.
I'm not sure what television is being referred to in this, as far as I know, there's no television adaptation. There's already a lord-of-the-rings-1978 for the animated film... so this should be used only for the 2000s era film series (much like the harry-potter tag relates to the entire series while there are individual tags for specific films in the series).
And this:
battlestar-galactica
Television series (twice - mid-1970s and mid-2000s) concerning the survival activities of humans against a race of super beings we created and lost control of.
All three questions are about the 2000s era show, so the tag should probably be changed to include the year anyways. If we get questions about the 1970s show, it should have its own tag to avoid confusion.
-tv
appendages, since for example there is no question here about the Buffy or Teen Wolf movies, yet the tags about the TV shows have those appendages. So a basic question would also be if the mere exitence of another version has any influence on the matter or only the existence of a question on this site. That's a problem which has not been discussed suffienctly officially, yet.