That is good news.
These plugs are unusual in that the threads are very long, and the hex head is very small relative to the diameter of the threaded portion. The aluminum pan causes the steel threads to corrode in place by electrolysis.
BTW, I have tried 2 methods to prevent the plug from seizing, and both worked equally well:
1) Grease the threads (multi-purpose grease).
2) Teflon tape.
One would think that the residual motor oil on the threads would be enough to prevent seizing, but this appears to get washed away, where the grease sticks.
Also, there is a tendency to over-torque drain plugs in general ('just to be sure'...).
With so much thread, very little torque is needed for a tight seal.
1986 300E 5-Speed 240k mi.