Is it true that you need 3 open lines of credit or credit cards to apply for a Mortgage?

My wife and I had our bankruptcy discharged in July of 2009 and per FHA guidelines you need to wait 2 full years after the discharge to apply for a mortgage. Recently a mortgage banker told us we needed to make sure we had opened at least 3 credit cards or LOCs before we apply for the mortgage. We each had two and prefer to not get back in to the old habbits. We have busted our a** to get our credit scores back up to about 680 and pay down student loan debt. So we applied for that banks CC and they declined us!! so now that will ding our credit. Is this an actual rule or is it just this bank playing hard to get? I'd be happy to move on to someone that actually wants our business. We have no consumer debt and have been waiting to get our first home for years. Thanks