Items listed for auction are family heirlooms...what are the heir's rights to these?

I came across several items of great historic importance to myself and family. I found that several documents are to be auctioned at an auction house this June. My father and his 3 brothers are the next-of-kin that is living from my great-great-great grandfather. The items for auction include a written probate document, a few family pictures, etc. What if anything can be done to possibly secure these items without having to spend a fortune? Do we have any rights in this case? Should I approach the auction house? Thank you for your suggestions.

I don't understand - are you suggesting that the items the auction house is auctioning off were stolen from the estate? If the items were stolen then the rightful heirs absolutely have the right to recover them, subjected to certain restrictions on time depending on where you live and when you became aware of the theft.

If, however, the items were legitimately sold by the true owners or otherwise rightfully transferred, then they are not yours. You have no rights to them.

The legal owner of an item can dispose of it any way they want. If the legal owner puts it up for auction, all you can do is talk with them, and if they are not ready to withdraw the item from the auction, then the best you can do is bid on the item or agree a private sale with the current owner.

You have no special rights just because the documents are important to you.

Items listed for auction are family heirlooms...what are the heir's rights to these?
None at all. And heirs' right is presumptive until such time as the grantor dies. Then that right becomes a matter of law.

Until such death there are not secondary rights.

So, that being said, you make no mention of who is offering these items for auction. Would you like to do that now?