Transmog question ?

So I'm an alliance character a Human Mage. I am heavily interested to transmog my kel thuzad sword into the sword Stormcaller (bought from Thrallmar/ HP (whici is the horde version of "Blade of the Archmage" bought from Honor hold).

So the problem is that it is a horde sword, not an alliance and it is stated that if you own the sword and you change factions it would transfer from Stormcaller to Blade of the archmage and vice-versa if u transfer from alliance-horde.

THe thing is i've seen lots of alliance players having the sword Stormcaller transmogged into their swords. When i ask them how they didi t they simply said they switched factions and the transmog was saved. Well i don't wanna do that since that would mean me spending 60 coins (going from Ally>horde then buying the sword, transmogging and then going back to ally again)

So my solution is to Buy the sword off of warmane coin shop. It costs 7 which is much lesser off a price.

So my question is:

If i buy the sword (Stormcaller) as an Alliance will it come to me as the sword i purchased (not as the Alliance version of it)and will i be able transmog it into my sword(since it's a horde one)?

I just dont' want to be wasting resources to something i can't get.

Please ask away if this is a bit confusing for you. Much thanks for the input!