Old or antique South-East Asian standing bronze Buddha, Javanese or Thai

Description

Old or antique South-East Asian standing bronze Buddha, Javanese or Thai.
I bought this lovely bronze Buddha at an auction in Israel. It is well cast with lovely crisp details and proportions.
The Bronze is heavily patinated.
At first, after receiving it, I thought that maybe the patina could be artificial. Using chemical and mechanical methods   I have tried scraping it off [upper part of thighs] but after all, it seems organic.
The Buddha is holding his right hand in the teaching mudra, the left holding his robe.
The style reminds me of early Buddhist models in South East Asia of the 8-9 century. However, this one is an enigma.
Size: weight  2280 gr
W =10 cm, H = 35 cm