Garrosh BOA Weapons = Don't do flex??

To start....I have already read the post about how Garrosh BOA weapon loot works, so please don't quote or link it.

Now...here's the main portion I am referring to:
•The heirloom weapons that drop from Garrosh are personal loot in Flex, Normal, and Heroic difficulty.
•The first heirloom weapon that drops for you will be for your current loot spec, but after that you will get one at random.

If I am to understand this, it means that guilds like mine (who are nearing Garrosh but probably won't down him next week), should NOT do flex as it might mean we might accidentally get the flex weapon which would then remove our "guaranteed first drop" and we would then be at the mercy of the LFR-Loot-Style-Gods that when we kill him on normal we will get a weapon, as well as we'll be doing a /roll between all the weapons (if we even get one of course).

Is this really how it's meant to work? Do a flex to learn/practice & get screwed on normal if you complete it? The wording from posts I have seen regarding the subject indicates so.

So, if anyone has seen a post somewhere either confirming this or rebuking, that would be nice.

A blue post would be the fastest way to solve this little question :)