No, the way the rule was publicly
summarised was that if you traded a first round pick you couldn't also trade a second round pick. According to the AFL, the full wording of the rule says "it is to be treated as a net result. If you trade out a (future) first-round selection, you must have a (future) second-round selection." The AFL said this was made clear to the clubs.
Link
So, for this to be anything other than misreporting by the Herald Sun:
i. Hawthorn must have breached the rules;
ii. The AFL must have inadvertently allowed the breach;
iii. The AFL must have compounded the permitted breach by changing the rule;
iv. The AFL must have come out and publicly lied about the 'real' rule, despite the other clubs knowing what they were told; and
v. in the face of that very public and easily disproved lie, all 17 of the other AFL clubs decided not to call the AFL out on the breach (or leaked it to the media), despite one of their most successful competitors gaining an advantage from the breach.
Or, the formal rule as given to all 18 clubs says it is the 'net result' that counts, so the Hawks satisfied the criteria by getting Carlton's second round pick, and some bozo at the Herald Sun - the paper that claimed Hird and Essendon were innocent for years - either misunderstood the rule or never had a copy of the official rule.
So, which do you think is more likely. If it's the former, I have some wonderful tin-foil hats I'd like to sell you.
