Legal Question in Wills and Trusts in California

Not necessarily. Some lawyers keep original wills so that the executor will come to them. (You can ask for it back while you're still alive.) The executor doesn't have to hire the original lawyer for the probate, but many do so. BTW, you didn't ask, but if you own real property or your assets are worth more than $150,000, you should consider a living trust so that your estate can avoid probate altogether.