I modded about 20 more Wii's and they all had D2C2 drives and they all looked a bit different, but there was a pattern!
If the large chip on the DVD drive is a "GC2" chip, then is is a VERY OLD D2C drive (moddable with ANY D2C compatible chip). If it is a GC2-D1A (like in Reezy's second picture), then it is a more recent drive and you have to look further to check if it's a D2C2 or not... Read on:
A typical D2C v1 drive has a second line of code written on the smaller GC2-D2C chip like in Reezy's 3rd picture. In later versions this second line was gone... and then it came back again in the latest versions. Only a missing second line does NOT mean that it is a new "D2C2" drive!
If the second line is MISSING on the D2C chip and the PCB has "MDK 337V-0" written right above the bottom flatcable, then it's 80% sure a D2C v1. Almost none of these drives have the metal clip on top of the spindle like in the picture on the bottom of this post. The ones that do have the metal clip are D2C2.
If the second line is MISSING on the D2C chip and the PCB has "APCB" written right above the bottom flatcable (linke in Reezy's 4th picture), then it's 80% sure a D2C2 drive. These drives come mostly with and sometimes without the metal clip on top of the spindle (the clip is not a 100% sure indication in this case).
In summary: The drives with the D2C chips with missing lines were probably made during a transition period. The metal clip is a sure giveaway for it being a D2C2. A combination of "no second line on d2C chip" and "APCB written on the PCB" also indicates a D2C2 drive (even without the metal clip).
If the second line IS WRITTEN on the D2C chip and you also have the metal clip like shown in the following picture, then it's a D2C2 for sure!!
The clip I was talking about is the one right above the white plastic cog in the drive. The one in the picture has a "2" stamped in it and is most often seen on DVD drives that have both lines on the D2C chip. D2C2 drives with a D2C chip without the second line mostly have a clip without anything stamped in it. This clip is a very good indication of a D2C2 drive.
Compare this picture with Reezy's first picture... Reezy does NOT have the clip and has both lines written on the D2C chip. So his drive seems like a D2C v1 drive. The only D2C2 drives I have seen that did not have a clip had no second line on the D2C chip AND had "APCB" written on the PCB.
i found this guide on another post! hope it helps!