a 2007 reference, not sure how good it will be:
http://wow.joystiq.com/2007/06/09/are-l ... ly-random/"Shaman and Pally gear didn't dropped for the wrong faction till the 2.0 patch. I still remember that Nefarian dropped a Pally chest for us after the patch, that was the first paladin item we had on the patch week"
@6 The UBRS Shaman drops don't really count, because any class that can wear mail can use them. He's talking about Molten Core and above, where if the Shaman gears drops, *only* Shamans can wear it. If there are no Shamans in the raid, then vendoring it or sharding it is your only option.
That being said, just afer 2.0 dropped, but a good two months before BC came out, they changed the raid loot tables to include all gear for both factions. Regardless of the fact that we had not shamans, and wouldn't for another month, in the beginning of december, we did a full clear of MC over two nights and had five pieces of Shaman gear drop. Great was the QQ'ing, and lo the GM did speak: Sorry, that's just the way it is. Apparently, the Horde were experiencing a lot of the same thing with Paladin gear.