Well, they are rusted for sure. But, still looks like plenty of meat left there. I would spray pentetrating oil into the splines and just keep working the driveshaft in and out many times to clear away some of the rust. Perhaps you might want to use a small screwdriver first to start the job, to prevent the driveshaft from getting stuck again when you have to force it inside the crank splines.
This is one of those engines that uses the regular type seal on the bottom of the powerhead instead of the carbon seal set up. You might consider replacing it now that the powerhead is off, at least give it a very close inspection prior to reassembly.
Once the splines are cleaned up, be sure to use a new oring on the driveshaft, along with the OMC moly lube on the splines to prevent this from happening again. Not a bad idea to pull the gearcase off every season (if used in salt water), to clean and relube the splines.
