New Duster

Hi all, I just purchased a 74 gold duster 78000mi (supposidly) on the /6 with a factory 3 speed on the floor:burnout:. You guys have a lot of good info on here and know ill be using this site a lot. Thanks for sharing your knowledge. Not new to cars or mopars but deffently no expert on either.
So first question for you guys. Where exactly should the engine id tag be. Id like to find out if it is the original engine. That way I know what way I want to go with it. If its the origonal motor I think ill try and restore it as close as I can. If not no rules!