Nice rocker KC! Does your cousin need any company on his/her garage sale excursions? I am sure there are many here that would like to get in on great deals like that rocker! I hit garage sales every week but have not seen a rocker as nice as that for the money.
Have you looked at this site http://www.nicholsandstone.com/OurStory.cfm
? Seems after the 1930s they really specialized in Windsor chairs and Boston rockers. This rocker appears to be a mix of both but I am not well versed in furniture styles. The stamp seems to be common on chairs thru the 1960s.
OMG! Look here if you want to see a totally awful refinish to an original N&S chair...http://pearlespainting.blogspot.com/2010/02/500-nichols-stone-windsor-chair.html