Advice on ‘74 Duster

TF360 said
A couple bits of info- I would ask if he changed the rear end because it came with a 7 1/4. The red in the interior is incorrect and pretty much devalues the car a little. Is the front suspension still factory or were there improvements? That being said, the color is very nice, and it has buckets and a console. Check for rust and see how it runs. I would offer 12,000 if everthing checks out ok

He doesn’t know what rear end it has and nothing is really correct on this car seeing what it used to be.
What’s the easiest way to check if it’s a posi or not, other than doing a burnout?
He said the suspension is stock but looks to be in good condition and says the car tracks straight and no werid noises. The car is about 4 hours away from me so I need to make time to go and see it.