As another Tolkien nominator, I would probably not read the disambiguation “Silmarillion” as just including the book unless it was explicitly included in the tag as something like “Silmarillion (single book only)”. I would catch it after reading the post here, but I don’t think it’s an obvious difference at first glance.

Trying to avoid becoming overwhelming with details, but Silmarillion as a term in both the books and scholarship often refers to both Silm and HoMe (along with other books like Unfinished Tales), outside of other context. The same has been true in many parts of fandom I’ve been in. I would worry that someone not reading back to this post would miss that it’s being used that way in this exchange.