There HAVE been 13's with oil loss issues too. I wouldnt just go on what a dealer said. I've heard dealers tell outright lies plenty of times.
By most accounts, Subaru doesnt even know why the cars with Fb's may end up burning oil.
If they all did, then we would know by now.
Your chances of getting a good one are probably better than with some other mskes, so if you want one go get it. But if I had to do it all over again I would go to a GOOD dealer like Mastro Subaru and buy a wrx.