Amendment to Living Trust: Can children take joint property not included in trust?

by Norma Rae
(CA)

My husband has amended his living trust, naming me as successor trustee in place of his children and has named his adult grandchildren as beneficiaries in place of his children.

All assets (namely, a residential property and a small savings acct.) acquired prior to our marriage is to be liquidated and distributed to the grandchildren. All assets acquired since our marriage are held jointly with right of survivorship, owned jointly (titles in both our names) or bank accounts in both our names.

Can his children take any assets held as described above? Do the amendments (which he had notarized) have to be filed legally?