As of now the Renault triber is not offwered with BS6 complinat engine. The Triber is periced between Rs.4.95 - 6.63 Lakh (Ex-Showroom Delhi). For the estimated on-road price from your city, follow the below link - Price.
There are 4 dealerships in Kolkata for Renault. Renault Rajarhat, Renault Kolkata, Renault Kolkata South, and Renault Kolkata Central. For their locations and contact details, follow the below link - Dealers.
For the availability in North Lakhimpur, we would suggest you walk into the nearest dealership as they will be the better person to assist you because it depends on their stock book - Renault Showroom.