Block 1 Section 83

I have an offer of $30,000 per NMA on this. My problem is that this is inherited property and I do not know how to find out how many acres I have. Is there a way to research this? My mom, who has been dead more than 20 years, had leased/sold? for a well that I get a small royalty on. If I own enough, I want to sell it. The company making the offer says 15.7 acres, but I need to verify that I can actually sell this.

My Wife has also inherited some minerals in this area but has not been contacted about leasing or selling her part. How can she connect with a legitimate broker about selling her share?