I don't know of any 16" multi-piece wheels that pose a danger of suddenly disentigrating unless they're rusty or damaged. The ones we call "widowmakers" are the 20" Firestone RH-5's, and they're used on bigger trucks. There are two styles of removable-bead wheels that were used on 3/4 ton and 1-ton trucks, one with a split outer ring that snaps over the main wheel barrel, and another that is a full circle with no split, with a relief area in two places that allows the ring to be removed and reinstalled. If you can post a clear picture of both sides of one of the wheels, we can offer a more informed opinion about what wheel you have. A typical 16" drop-center wheel intended for use with tubeless tires will be too small on the inside diameter to fit over your brake drums. If the 62K mile figure is accurate and the truck hasn't been abused, it's very unlikely the multi-piece wheels will pose much of a problem as long as an experienced tire shop with the proper safety equipment works with them. Once a tire is installed properly and inflated to the correct pressure, the wheels will be perfectly safe during normal use. Never, EVER try to add air to a tire on a multi-piece rim that's flat or seriously low on pressure!
There are some brake upgrades available with a moderate amount of modification to deal with the scarce supply of parts for the original-equipment brakes. Fairly recently, a disc brake conversion for the front end has been developed that retains the 8-lug wheels, and there are several later model rear axles with newer brakes and better gear ratios that can be adapted to a flat bed truck. A GM corporate 14-bolt axle from a cab and chassis box truck, or a class C motorhome is one example.
Jerry
