I went out to Jones cemetery this morning. I walked around for over an hour. Could not find any Baldwin graves. This cemetery is not kept up. Alot of the older graves are barely or not readable. I did notice that someone submitted a subscription of all of the graves in February of this year to rootsweb. They didn't find a Baldwin grave either. It is apparent that there are quite a few unmarked graves.
This is a very long shot. You might try writing and asking whether there are any Baldwin graves in Jones cemetery to:
Kennedy Memorial Gardens Inc
5513 Cadillac Dr
Austin, TX 78724-8519
I did not notice any mailboxes at the cemetery, but the address is what the Travis County Appraisal District has.