Have been going there for the past several years; as of late (since the last proper librarian departed) things have taken a turn for the worse (and they were already bad).  Those currently in charge of the collections do not know how to find materials; many volumes are missing; the rest are in bad shape.  Last time I went (last summer), they asked for a Rs 200 'donation' for each manuscript I asked to see.

However, all that being said, it is possible to see the mss.  Officially, one cannot photocopy or photograph them, but it does happen.  If you need materials from there, I would suggest going in person (or sending a very persistent and knowledgeable proxy), and being prepared to go into the collections and look for the materials yourself (though again, that's not supposed to happen).  

Effective working hours are 11:00am to 4:00 pm.  

Best,

Tyler

PS- Am writing an article on the NPS on exactly this topic.