Grandpa's old 1923 Mah jongg set

This is my grandpa's old mah jongg set, he passed away about 2 years ago, and my grandmother moved to a retirement home, so basicly the old house is just filled to the rafters with antique junk. Me, my mother, and my aunt are going to clean out the house this summer, keep the family antiques or memories, and sell whatever's left at a yard sale. I remember playing with this thing since I was 10, and now I'm quite curious to see what this is worth, or the history of this thing. Internet searching has failed on me, so I'm counting on you guys to help me with this thing. All the pieces are ivory on bamboo or just soild ivory, not bone like other people think. The art is hand carved on the ivory, and i'm pretty sure the emblem is stenciled. has the original "how to play" panphlet from 1923, and I think the set is missing some extra pieces. Made by Gibson Art Company.