Can anyone tell by looking if a new satellite dish has the same hole placement for mounting as the old one so that it would be a direct swap without having to cover over the area and find a new location for mounting the new dish?
Dwayne,
VERY unlikely.
Best answer in most cases is to get a 1/8" thick piece of aluminum sized to span the whole area. Paint one side white so it matches the roof. Drill holes every three inches or so around the perimeter so you can use SS screws to attach to roof and bed in a good polysulfide. Use it to cover up the whole area.
A wineguard HD satellite antenna has a large base that would cover the area of your old one. I would fill in the old holes with roof sealer before sealing a new wineguard antenna over the area. We did that with one our coach. We took of the motion satellite and replace it with a HD unit.
Bob