My 02 2500HD with the 10.5" rear axle did not have a magnetic drain plug. I bought one for a 11.5" axle GM #12471479 and installed it tonight. The 2 plugs side by side are very close. The magnetic plug has a rubber ring/flange around the head where the non-mag plug did not. I didn't take pics of the 2 plugs as I should have, but it works fine.

When I change the fluid again I will get a pic if I can remember. Just posting for info/reference in case someone else wants to do the same.

Does your '02 have the locking differential? I thought the magnet was to pick up the metal slivers from the clutch steels. Like you, I think all should have the magnets. Thanks for the info...

Yes, it does have the Locking rear G80.

My '02 gasser has the locking differential as well. If I recall correctly, when I changed the differential fluid last year, the plug has some metal shavings so it probably is magnetic. However when I changed the front differential, it had alot more metal shavings than the rear did. I guess front end is prone to more wear such as when binding on dry pavement.