The Ravel orchestration of Mussorgsky Pictures at an Exhibition is under copyright in the U.S.
Only the orchestra parts supplied on rental by Boosey NY are legal.
There are two printings:
1. The original ©1929 parts.
2. The ©2002 parts.
You may find that the older part does not match the 2002 score and parts now being rented. Unfortunately the un-named editor of the 2002 edition did not fix the placement of many of the pedal marking.
38 different orchestrations of Pictures are listed at