Exactly what makes a MOPAR a "Matching Numbers" car?

I ordered a new 70 Duster slant car Dec. 26 1969. Lucky me, when it arrived it had a 426 hemi....the dealer said they ran out of stants that day and there it was with my hemi!!!!!! True story! :steering:
Yo!!! wake up Hey!! wake up. You have to be dreaming. There is no way they could have built two 70 Dodge Duster's the same . What color was yours?
Did it have the special HP 904 trans with the 8 3/8 Dana built track lock rear. I have pictures of mine . If you look close you can see where the Hemi was in the front. I'm working on it slowly and hoping to have it back the way it came. I'm in need of a parts car. If you know of any please get them for me.

047 (2).jpg