The answer will depend on your MLS Rules, specifically Section 13 of the Model MLS Rules, which is a mandatory rule.
Your local MLS can adopt either of two options in Section 13. One option allows an MLS participant to use sale price information from the MLS in advertising. The second option has limitations, and does not allow an MLS participant the right to include information about specific properties listed or sold by other participants.
Both options require the advertisement to include the time period for the information and where it was obtained from using the following, or substantially similar, format:
Based on information from the (local) association of REALTORS®/from the (local) MLS for the period (date) through (date).
Be sure to check with your local MLS to find out what your MLS Rules entail. Texas is a non-disclosure state, but that only means that sale price isn't public record. Your MLS dictates how sale-price data is used.