Your blessed. Your grandfather has left you a wonderful family heirloom and a very rare and sought after collectors piece.
Add to that, that given its size and classic lines, it is today a very wearable watch which will be admired by all, I am convinced that no matter how much thar restoration in Schaffhausen costs - it will most certainly be worth it.
Of course, not everyone has the means readily available to spend significant monies at any given moment on a watch restoration (or a new watch) but if at all possible you should consider it and/or save up towards it.
Happy for your find. Wear it in good health and be proud of its origins.