Oliver Cowdery, when copying to the printer’s manuscript, switched the order of never were to were never, which represents the more common word order in modern English. Elsewhere the text has examples of never before the finite verb as well as after it, although the first type is more prevalent in the Book of Mormon text. Here are the 13 examples where the subject is the pronoun they (including Alma 63:8):
never precedes the finite verb
follows the finite verb
In one of these cases (Alma 44:19), the 1874 RLDS edition shifted the never to after the finite verb (see the discussion under that passage). Since either word order is possible, the critical text will restore the original order here in Alma 63:8, “they never were heard of more”.
Summary: In accord with the reading of the original manuscript, restore the order never were in Alma 63:8 (“they never were heard of more”).