On the TX Confederate Pension Index there is the following:
Dennis, William Thomas -- # 39731 -- Brown Co. Dennis, Mollie -- 50629 -- Brown Co.-- husband -- William Thomas Dennis.
Looks like your couple, and I would send for copies of his pension, and her widow's pension applications.They often contain lots of good stuff.She would have to give info on her marriage to prove she really was married to him, and eligible for widow's pension.Names, dates and locations are often in pension applications. William may say where he was born.Mollie will probably give date and location of her marriage to William. Remember they are older when they apply for those pensions, so some of the info may be "off" just a little -- I've seen that happen.Sometimes letters are written by their pastor, or neighbors and state they know the couple were married, or something similar.Those can be very interesting.
Follow up with census research, too.You will pick up names and info on other children.AND, you never know who might live with them.Older relatives often live out their "golden" years with younger family members.