Offer to purchase our "royalty interest"

We are a small church that, years ago, was deeded a lease in Borden County, Texas and have received a letter stating interest in buying our royalty interest. I am trying to gather information on whether this is a legitimate offer, and or if we should hold on to the property? I’ve seen that usually the next question is location, so here that is, E/2 of Sec. 45, Blk 25, H&TC RR Co. Survey, Borden, County

What do you own? Your post says that you were “deeded a lease” which could be a leasehold interest such as an Overriding Royalty Interest (ORRI). You also say that someone expressed an interest in “buying our royalty interest”. That could mean a Non-Participating Royalty Interest (NPRI). In order to determine whether an offer is “legitimate” we would have to know what you own. (What does the deed say?) There are at least 6 wells producing from the E/2 of Section 45, Block 25. (4 Horizontal and 2 Vertical). Normally, an unsolicited offer in the mail is a lowball amount.