They will sump, and Kudos to you Sir for actually checking the oil before starting a bike that has sat for a long time
You can pull out the neutral safety switch from behind the belt pulley and see if oil comes out or use a bent wire in the hole. If there's oil in the crankcase, I'd fire it up for a few minutes and re-check the level. If it shows oil then, I'd warm it up, ride for a few miles listening for noises and check it properly.
Motorcycle engines don't have the same type of solid bearings that cars do (except the rod). They will live with almost no oil pressure for a long time because of the roller bearings. I wouldn't recommend it! Just sayin'