I would be interested in hearing a recording of the station you are describing. It does not fit the format of any station that I am aware of, or possibly I am misunderstanding what you are describing.
The AM carrier you describe might have been Chinese numbers station V13. V13 transmits in USB+carrier and would have been on that frequency at that time (1200 to about 1231 UTC). It would have also been on one hour later, starting at 1300 UTC. V13 starts with pipe music and sends numbers in duplicated groups of 4, in a female Chinese voice.
T!