I put on new alloy wheels and needed a different set of lugs. That's been the case with every steel to alloy wheel swap that I've done. The alloy lugs that I've used have more of a sleeve or neck that the wheel actually rides on.
Be sure to keep at least one set of steel wheel lugs on the van once you swap over since the spare has a steel wheel.
When I bought ours I got a set of steelies for snows, 1 dealer said I would need different lug bolts, but before putting the snows on I did some searching and found that the p/n for the lug bolts were the same for alloy to steel.