The number of clips really doesn't matter, as long as there are at least 3. What does matter is the wheel/tire clearance to the tie-rod end on the front end.
To maintain clearance, you need rims with the proper set-back. Measure this by placing a straightedge across the back side of the rim and measure from there to the mounting face, the part of the rim that sits against the brake drum. You need to find some wheels that are close to the originals. You can go with less setback, as long as your rear tires don't rub the fenders.
Most modern gm 6 bolt wheels will accept your hubcaps. If they don't have the clips, you can put your clips on newer rims without a lot of work.
