My understanding (*willing to be corrected with evidence) is that the first letter is always the wide version and the second and third letters are the narrow version.
The same thing is seen on the Birds series $2 notes, though the narrow version also appeared in the first position. Your catalogue makes a brief mention of the matter. I suspect someone has written an article on it for the CPMS Newsletter/Journal at some point but I haven't looked to see.
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BWJM, F.O.N.A.
Life Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
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