I am looking for a 1970 Duster rally dash thumbwheel radio. Are there any other years that will work? It seams like the 68-69 Barracuda radio is similar but the push buttons are different. Will it bolt up?

The 68-9 Barracuda radio is the exact same, other than the dial face which can be easily swapped . The 68-9 Barracuda and 70 Dart Swinger 340 / Duster 340 use the same fat chrome push button (same part number on the buttons) I have these radios if you need one .
If you look at my website, I have one pictured about half way down, on the left .
http://wardsclassiccarradiorepair.com/

Only diffrence is the 70 dial face plate will say Chrysler
instead of Plymouth . I have tons of face plates as well .

Greg