Harley-
Welcome aboard! I am fairly new to this forum as well.
First off, you didn't say whether or not this Bronco is IN California.
If it is out of state, in a non-smog required state, then you may be missing a lot of the smog equipment.
You can round up all of the equipment and do your best to get hooked back up. The only way a ref will even consider an exemption is if all of the year/veh. specific smog equipment is installed. They won't even consider an exemption unless everything is hooked up, and you have spent a certain amount in parts trying to get it to pass.
I live in Cali, and recently bought another Bronc. When I was searching I didn't even consider a Bronc that required smog. Too much of a pain in the arss because there have been too many years where the system could have been butchered.
I ended up buying a '69 from out of state.
When I went to register it at DMV, the first thing the lady asked was if it passed smog. SHe didn't even know the years of smog requirement.
I think in the long run you'll be happier buying a Bronc that has NO restrictions on it. When I am ready, I will be swapping my 302 with a 351W again (as I did in my previous '73). Great upgrade you can't do if it has to pass smog.
ALSO- As far as having the seller get it smogged before the sale (unless sold 'As-Is') you should be there when it is tested. I know of one horror story personally where 'Cooter' from 'Cooters Garage & Laundry Land' fudged the smog cert for his good ol boy. Two years later when it came time to get re-smogged, Cooter's smog license had been yanked by CARB and he was fined into the stone-age. It took a year for my buddy to round-up all of the smog equipment, install it and make 3 trips, 60 miles away, over a period of 6 months, to get it exempted by the ref.