These pacs are labelled with a letter that indicates the type of chain followed by a number that gives the drivelink count but the letter just seems to gets you to a range of chains with the same pitch and gauge. Any way to tell what kind of chain it is (chisel, semi-chisel, etc.) without pulling the chain out and looking at it? Something you can't do when ordering online. Also is there a recent update on the letter designation? For instance, a G66 and a M66 are both chains with the same pitch and gauge, has the "M" replaced the "G" or is it a newer update to indicate a different type of chain?