You will have no problem finding one. It's a VERY common radio.
You are looking for a 2884759 with the Black pushbuttons (the 70-71 carries the same number but has chrome push buttons)
I may be able to hook you up with an NOS one ,
Or if you want to snag one on e-bay and send it in let me know ,
I think the only ones I have in my inventory at the moment are the 70-71 .
You can visit my E body radio ID page to learn all about the diffrent E body radios ..
http://wardsclassiccarradiorepair.com/id15.htmlHere is a pic of what you are looking for ...
Greg