Ok, Doug, then your full cylinder should weigh no more than about 38.25 pounds. If it's been overfilled, then bleed off enough to reduce the weight to that point. Do so outside in a well ventilated area with absolutely no source of spark nearby. Since you have to bleed through the tiny hole, it'll take a while, depending on how overfilled it is.
If it has a bad OPD valve, you can continue to use it safely until it's empty, but then you should have the valve replaced at a full-service propane dealer. If you have aluminum cylinders, then they'll likely have to special order the proper OPD valve.
You can also test the rig's regulator by simply hooking up the cylinder to a known-good barbeque grill that has its own regulator.