Hi Keith,
Thank you for asking.. When researching Thomas H Roberts, This is the biography I gleaned from the references. Sources I found, listed him for the Alamo. A couple of sources went further, which I put into the biography.
1) Thomas H Roberts was assigned to Capt Chenoweth's command Jan, 1836 at the Alamo, which must have resulted in a list..
2) Later Capt. Chenowith was assigned to Goliad after Chenowirh's commanding officer was killed and put in charge at Goliad.
3)Our Thomas H Roberts, a marksman was re-assigned to Capt. Baker's company and entered the Alamo compound as one of James Bowie's troops.(his name may still have been on Chenoweth's list, even though he was reassigned).
Alamo sources list him as being killed in the Battle of the Alamo and Texas General land office investigated this also with their notes.
I would point out that no one survived the Alamo, except a Mexican American man who talked the Mexican Army into freeing him, as he said he was a prisoner.....