H1B Dropbox - urgent

My H1B Visa expired in August 2020 and now I hold an approved i797A valid till 2022…

Now, My spouse & child under 14 can attend Dropbox (they too had Visa stamped and expired in August 2020) and get their Visa stamped based on newly approved petition ?

Because, the Dropbox confirmation page says we should attach "Photocopy of each parent’s valid U.S. visa page (applicable for child

below 14 years)" but I (H1) do not hold stamped Visa.

can anyone confirm please?