You may not need to replace the wheel bearings right away. I don't find very many bad ones. They're easy to check, just stick a finger in there and rotate them. If they're smooth and have little to no play between the inner and outer race, they're probably still fine. I do plan on replacing any of the steel shielded or open bearings I encounter in some of the older wheels, but I don't necessarily do it immediately. Also, if you have the rubber shielded bearings (which I think '77 models did), you can just add some fresh grease. The rubber shields can be popped off with a pick or little sharp pocket knife.
Steering bearings, yes, most need replacing. I think the problem is they were never greased since they left the factory. Do install a grease nipple in the side of the neck while things are apart so you can easily keep the new bearings lubed. I consider it an integral part of the new bearing install process.