I inherited my grandfather's goose gun after he passed, I remember going hunting with him when I was younger and would like to take it out at least once for a goose hunt to relive those memories with it. My main concern is will steel shot be ok to be fired in it? Don't want to mess the gun up if it will not take that type of load.

No. It is bismuth time.

I have had one when they first came out in Kmart.
In the early '70s $99 in the box.

When they made the first steel shells they were crap. If you overwintered the shells the shot would collect moisture and rust to gather into steel slugs.
But that is what we had to use. My goose gun now has a ring on the outside and way less choke on the inside, BUT.
The gun will function just fine on today's steel loads.
I still use it from time to time and shoot MANY very high powered 1 1/4 oz steel BBB hand loads. The clip is an issue but it never did feed well and a bolt really sucks on a bird gun.
I have used it a LOT of deer with a full 1 /14 oz slug. 100 to 150 yards...
Shoot it I know you have a lot of memories but the gun is still only worth $99.


PS

With the gun SOOO light and 3" goose loads you want to have a GOOOOD recoil pad on it
It kickes, and will leave a mark.

For as little as it sounds like you want to shoot this gun, Randy is correct. Get some no-tox other than steel. Enjoy the memory chasing as that will be a great time for you to think about your father.

TY all for the replies.

And it's worth waaay more then $99.00.

I sold one in ten gauge 7-8 years ago for $350. That was likely too cheap as my email blew up with buyers after it was sold.