The main thing is the oil in the compressor, and if the unit was in cold environment it needs to warm up to room temp for the oil, mainly, and hopefully the liquid refrigerant didn't migrate into the compressor. This will cause slugging the compressor, (trying to pump liquid.) There isn't a lot of refrigerant in the system so that may not a real problem. Yeah, let it stand a day or so. If you really are in a hurry you can remove the back panel and put an air dryer to warm up the compressor and boil out any liquid. And make sure the cover is back on before starting it up. You should be okay, but err on the side of caution.