There are a couple ways to see if it is loaded. Odds are if it is the ammo is toast looking at the gun, but considering the condition of the wood, maybe it survived. Eject the magazine and see if there are rounds in there. If you can't get it or it is froze it isn't like it has a hammer under tension ready to contact a firing pin. I've had tens of thousands of rounds or more around through the years and not one has ever popped on its own. The one that may be concerning is the chamber. You can either grab the charging handle and with draw the bolt and visually check. Or, option B. You can take a cleaning rod, or even a dowel down the barrel (as long and it isn't to caked with gunk) until it stops. Mark either with a marker, a pocket knife, a small dab of paint, or use the Chatlie Tuna approved method of putting your hand right at the end of the muzzle when it stops before you withdraw it and line it up on the outside of the barrel. If the end of the rod goes all the way to the bolt face, you are 100 percent good. If you are having a hard time telling let me know and I can measure one for you that hasn't been in a lagoon for 50 years and get you a measurement.
Charlie