Oldsmobile diesels were regularly converted to gasoline. Mondello sold a kit for a while. Of course, Olds gas engine heads and intake were a bolt-on and the diesel block retained the distributor drive provision (there was a vacuum pump in the hole that also drove the oil pump) so it was an easy swap. Change the cam, add a distributor, flush the fuel system, and you're good to go.
A 6.2 is a dedicated diesel. There are no gasoline heads that fit and the diesel combustion chamber is unsuitable for gasoline. Can it be done? Sure, given enough time and money. Is it remotely worth it? Well, the result will be a heavy gasoline engine that was expensive to build, with crappy performance.
Again, if the engine is based on an existing gasoline engine, the conversion is relatively easy and inexpensive. Converting a dedicated diesel is not.