Hi Shahid. No, notes of Rs. 500 and 2000 are not accepted in Bhutan as valid modes of payment. You will have to exchange the currency when you reach Bhutan.
Denominations upto 500 are accepted in Bhutan. on bordering towns, like Phuensholing and Samrup Jongkhar, even 2000 notes are sometimes accepted. also, exchange rates are same