Well, if we need to talk about what is a special rule, then so be it.
Let's read BRB p.66, bottom left margin:
That means that a minority of special rules are NOT in the special rule section p.66 to 79.
What you describe is a house rule. It is certainly not a correct BRB interpretation, since the BRB mentions that some special rules are not in that section, as I recalled above.
If you want to know better what is a special rule, in the BRB sense, then better read p.66, bold paragraph below title:
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Back to original discussion,
In the case of Flaming Sword, it conveys 3 effects: (1) +1 to wound; (2) magical attacks; and (3) "the Flaming Attacks special rule".
All three effects are certainly uncommon rules to govern uncommon circumstances. They are all three special rules, according to BRB and despite some commonly played house rules.