Buy it! B-West AK's have a couple of different receiver markings. The receivers marked B WEST LA CA CHINA have properly heat treated receivers and are assembled with Chinese type 56 parts and assembled in the California. Receivers marked AZ (Arizona) are "supposed" to have improperly heated treated receivers and need new receivers which are available for replacement by a qualified gunsmiths. Even the AZ marked rifles are assembled from Chinese type 56 parts and if you had to replace the receiver, a type 56 parts kit is worth far more then the asking price of the rifle. Go for it!
The above information has been gleaned from multiple Ak web sites. I too, bought a B West Ak, marked LA CA CHINA and had a good old fashion panic attack thinking I got hosed on the deal, I burned up the internet to find the information to decide if I was burned on the deal. At least 2-3K rounds have been shot thru the rifle with no peening of the ejector or elongation of the hammer/trigger pin holes elongating.
My opinion for what it is worth, buy it and even if you have to replace the receiver, you'll the closest copy to a type 56 you can find. Good luck.