could try checking bottom of the passenger side frame rail in front of the rear axle. pretty sure there should be a vin there or i think i seen numbers there on my 81. not sure if it would be the same on a 70's frame but i also know 70's vins are a bit different

 

I'll check there. Thanks

 

Could be just the hood from an 83, from 79 to 93 the hoods exactly and directly interchanged. Grill was the same 81-85, front and rear diff would interchange 72-93 whether disc or drum, should be able to swap the spindles for disc brake version, housings themselves didnt change.
Chevy used Dana axles too, I know a guy who had a 79 w 200 and swapped Chevy spindles and calipers on to it.