Wife bought a 308 win with a 20'barrel; thought she had to have one, picked up some 180 silver tips and power points from my dad made in the 80's will they work for elk under 300yds?.
180g Power Points worked for my son-in-law closer to 400 yards. He was shooting into the sun and the haze/mirage from blast gases obscured our vision for a second. The cow was on the ground before our vision cleared. Basically a classic bang-flop DRT.
If the ammo was stored well (i.e. in a cool, dark, dry place) it should be fine and the shelf life will be measured in decades. Extreme temperature swings and humidity (wet) are the primary dangers to long term storage. UV rays, not so much and anyplace indoors is generally good UV protection.
If the ammo shows signs of corrosion, if the the storage was not temp controlled or there are other reasons to suspect the ammo may have been poorly stored, it should be inspected carefully before shooting it and possibly disposed of without shooting it. Most likely it is safe but a new box for the hunt might be advised regardless.
My concern would be a squib load resulting in a bullet stuck in the barrel, followed by another load. Bad news. My other concern would be inconsistent performance due to some degradation of the ammo, In any case, I would use the old ammo for practice and get a couple new boxes for final practice and the actual hunt.