Quote:

It has been my observation (and I may be dead wrong on this) that the 1970 Dart/Demon had a lighter silver grill (that coordinates with the '70 Rallye wheel centers), while 1971 Dart/Demon had a darker silver grill (that coordinates with the '71 Rallye wheel centers). You may need to look at a '70 and '71 Dart/Demon side by side to notice the difference.
Can anyone confirm/deny?

That would be a no. The same silver but 71 had blacked out center.