I'd test them. Toss some in water and let sit for about 15 minutes. If they sink, they are likely still viable. If they float, they are not viable. Then take your sinkers if you have any, and actually sprout test them. You can figure out what your germination rate is from that.

Squash seeds have a fairly long life even at room temperature (some of mine were still good after 10 years) and potentially much longer if refrigerated or frozen. IF the seeds were completely dry when stored, kept in a sealed container to keep out moisture, and warmed to room temperature before opening. The moisture from food in the fridge can damage unsealed seeds, regardless of temperature. If the seeds were good to start with, and stored in an air-tight container, chances are the germination will be good.

Really good info thanks! They were not in a good airtight container. They were in plastic bags.

Do they need dark to germinate? I never heard of this but noticed some sunflowers said this on seed packet?

Some seeds (mostly small-seeded greens) need light to germinate. Most other vegetables (including sunflowers) don't. That is, they don't NEED darkness, but they don't need light either. Not well appreciated is that among these other vegetables, strong light can make it a bit harder to germinate. The light tends to purge the seed coat of oxygen and can dry it out. Of course this is only relevant if the seeds are not well buried in soil. If they are, it's pretty dark down there.

Thanks! 2 different sunflower seed packets said specifically they needed darkness to germinate. That was a new one on me!

Curious how accurate the water test is? I tested a new sunflower seed packet from this year and zucchini from last year. 4 seeds each. Zero floated?

I have no idea how accurate it is for sunflower seed. Sunflower seed can have air pockets and somtimes don't- black oil almost always floats and so is an effective bait for drown buckets. Some sunflower seed can sink too, depending on the variety. But since your zucchini seed is still fresh from last year, I'm not surprised they sunk. Did you test your butternut squash seed?