Someone can correct me if I'm wrong about this. Brongersmai do not have subocular scales under their eyes. They have longer supralabial scales that go up from the lip and make direct contact with the eye. Borneos and Sumatrans have subocular scales underneath their eyes.

I've noticed animals for sale that are listed as "bloods" or "Malaysian" and if you look closely you can see they have subocular scales, which I believe means they are either not bloods (meaning Brongersmai) or they are intergrades.

I find it hard to tell the difference between sumatrans and borneos though, and intergrades.

Correct me if I'm wrong.