Now I know who bid me out by this one. It's a 19th century Burmese dha iwe but not a story sword (it's not a story told by the koftgari work). The hilt isn't a replacement IMVHO but like you said byself missing most parts, also by the present silver part is missing something. Nothing at this dha is Thai, sorry Marius. To restore the handle will be a challenge, good luck for this. I would start with the blade and polish the parts without koftgari. Your sword will has looked similar like this one:
http://arscives.com/historysteel/images1/226-mib17.jpg
Here you can find also others in the same style:
http://arscives.com/historysteel/con....swordlist.htm
Regards,
Detlef