In SE Asia, the variables for glass beads are that they are either imported from China or India, or they were locally-made. There were, formerly, glass-beadmaking industries in Thailand and Vietnam.

"Khmer beads" only indicates "worn by the Khmer." It is not an origin.

The beads look like plain furnace-wound glass. Without something like a chemical analysis, and a corpus of analyses to compare with, not much more can be determined. All plain furnace-wound beads look more-or-less the same, from any industry. But most of the oblate beads I have seen from this region look Chinese to me.