Swiss, sorry that I intercept, but hatch borders in your pictures must be corrected in connection with the body curvature. The same concerns also inscriptions. Forgive my English it is bad - I'm a reader, not a writer!
2 Swiss: Thanks for your job! It's a great one! But you've admitted small discrepancy - in the official site of SCAC (the correct abbr of Sukhoi Civil Air Craft) this craft named as SSJ100/95B vs RRJ 95 on your picture. http://www.sukhoi.org/company/structure/rj_sukhoi/ - I send you a link to russian page course it contain more exact info.
swiss, IMHO the nacelle on 95001 was complitely white. Light-blue (not painted!) panels had mounting instead off original white-painted in the test flights. There was many variants of panels equipped different sensors to register parametres of engine work. http://sukhoi.superjet100.com/gallery/photos/
swiss, as I write earlier, there was many variants of makeshift nacelle panels with built-in sensors to register engine's work. Not painted composite panel have light-blue color. If you look your photo closely you may see light-blue hoods on inside of nacelles. They are not painted too! Just as jets. If you can't believe me you may look picture in up-right corner of official SCAC site start-page: http://sukhoi.superjet100.com/ Painted therein plane has completely white nacelles!