The conversion is simple. There is no metal work required unless there is corrosion repair in the typical areas at the base of the A pillar. The issue is getting the trim to fit in the rubber gasket. It is difficult to get the trim to seat properly in the upper corners....However, bellagt seems to suggest that this isn't a simple conversion. Still, if some metalwork is needed to do this conversion, doing it in conjunction with rust repair and paint would make sense.
BTW, with Prosource out of business, glue in windshields are also near unobtanitium.