If you have all the donor parts from the hardtop, it's a bolt in affair, the post is merely spot welded in place, the side glass from any 69-70 B-Body HARDTOP, including the Charger will interchange, the 68 B Body side glass has a much more narrow runner on the glass tracks, so avoid 68 componets, I recently converted a customers 69 post Coronet using 70 Charger regulators and side glass, including the vent window frames, you'll need to cut a "clearance" slot for the rear qtr windows to roll down in the upper door jamb on the post car, which is covered with the rear qtr window jamb gasket from the hardtop donor, simple surgery,....actually much easier to convert a post to hardtop, than visa/versa,...besides the hardtop IMHO is much more visually pleaseing on the eyes than a post model