Do I need to use copy when working on the same dataframe?

I was wondering if the copy method are useful in the following cases:

df_av = df_av[['plan_name', 'ADO_ver', 'ADO_incr']].copy()
df_av = df_av.dropna(how='all').copy()

Are these lines equivalent to:

df_av = df_av[['plan_name', 'ADO_ver', 'ADO_incr']]
df_av = df_av.dropna(how='all')