2007 April 27.
The balance and its components:


The rim and the arm, the golden screws, the hairspring, its stud and collet, also the safety roller were original. All over age related marks, but they can be to eliminate.

The staff and the impulse jewel were not original.
The staff sticks in the balance pierced stud, on it the safety roller. Both were cemented with shellac. Instead of an impulse jewel fits a piece of steel in the arm hole, also cemented by shellac. The inner and outer curve of the balance spring were altered. The inner one ends unequal (yellow line photo 5), the terminal curve was bent far out (red dotted line).