The interesting thing is that it’s using an FET driver with an SO8 FET. That didn’t happen for quite some time. The “original” originals all used a 3-channel buck driver. Next there was a wide variety of drivers in the various clones, imitations, or simply new production units (IIRC). Eventually the JB driver showed up and that was using a TO-252 packaged FET (eg the big one). Eventually a modified version of the JB driver finally switched to SO8, probably due to the cost at that point (SO8 had long been “very common” for commercial stuff by then!). By that time (January 2014 we’ll say) I think that the flood of poor SRKs was well underway.