The original Khmer style is lost. What we see now, I believe (especially with this "Bokator" AKA Hapkido/Muay Boran/Tony Jaa mixed stuff) is a modern recreation, with obvious influence from Muay Boran and the Tony Jaa fictional style he created for the movies. The creator was a Hapkido teacher primarily, and in the U.S. at that, after living in Thai refugee camps. The Khmer (not all Cambodians are Khmer) had their greatness 1000 years ago. But then Thailand was in control of the region and their country for 100's of years until modern times, after Western intervention. A lot of Thai culture was transferred to Cambodia during this time (and the other way around), and Muay Kadcheuk or BKB was in fashion. The entire region is influenced by Indian Kick-boxing (Malla-Yudh) so they are all similar anyway. There was also some exchange between Thailand and Myanmar. The stories mention Thai fighters beating champions in Myanmar (and the other way around), and both adapting their own styles. But how much? Muay Boran also includes head butting and used to be a lot rougher before the sport rules. Again, the entire region is similar. Even in Thailand alone, there are many different styles, especially with the Muay Boran and Jeurng. From my own research (I live, study and train in SE Asia and have been to many temples with martial art images in each of these countries) the older style of Cambodia was most similar to the Tamil style Varma. Varman was a title for a martial expert. ("Varman or its variants, Varma, Verma, Varman, Burman or Barman, are surnames that are used in India & South-East Asia. According to Radhakanta Deb, the surname is derived from the Sanskrit word for "Shield, Defensive armour". (Wiki) There are Tamil websites discussing this in great detail. And you can see this title in many of Cambodian Kings names. There is quite a lot of Tamil influence in Cambodia during the Khmer time of greatness. There are also many similarities when you compare the Tamil and Cambodian temple images especially. And most of it is grappling, not kick-boxing. There are even Cambodian teachers in YouTube videos showing the grappling interpretations of the images, but not kickboxing. Cambodia has preserved its traditional wrestling, but the kickboxing seems to be more modern, with some Thai influence. At least, this is what I have noticed so far. Doesn't matter. There was a lot of influence back and forth for a long time. Consider, All of SE Asia is smaller than the U.S. Not so difficult for fashions and styles to spread in such an area. And also we can find people playing guitar all around the world. Similar instrument, but each region has their own way of playing too. Now the entire regions kickboxing is similar. But there are many local kick-boxing traditions that are similar, but still unique to each local area.