I recently obtained a block which I am told is a dss 306. I have been informed by a friend that dss does not make their blocks and it is either a shp dart block or a boss block. Regardless my main concern is that it is in fact an aftermarket block and not a stock block. Can anyone tell me what I can look for on the block to confirm that it is at least not stock and then which dss block it may be? I greatly appreciate it!