It is magentized!
The curiosity drove me crazy today so, when I got home from work, I drained the final drive oil again and cleaned off the plug bolt. It sure enough has a magnet installed in the middle of it and it was covered with metal particles. Must be something new they are doing (although it did not have one in the engine...??). It also did not have a pressure washer on it so I put one on.
What concerns me now is that the final drive oil was rather dirty again after going only 100 more miles since I changed it at 630 miles. Granted, I did not clean off the plug last time and the final drive is clearly breaking in but should the oil be dirty again already? I think I'll change it every 500-1000 miles for a while and watch it.