Hi - I recently purchased several Little Golden Books in an auction. In the lot are two "The New House in the Forest". One has a blue spine, the other a golden spine. From what I can tell, the one with the gold spine is a first edition? On the back page it has a letter "D". What does that mean? Also - the book is in really good physical condition. The spine is in tact and firm, however, there is pencil writing on almost all the pages. Does this hurt the value - should I try to gently erase the marks? Any education on Little Golden Books would be great!!