Step 1: Recall packing efficiencies of common lattices.
The packing efficiencies of:
\[
hcp,\ ccp,\ \text{and}\ fcc
\]
structures are all:
\[
74\%
\]
Step 2: Understand the relation between fcc and ccp.
The cubic close packing \((ccp)\) arrangement is actually represented by the face centered cubic \((fcc)\) lattice.
Thus,
\[
fcc \equiv ccp
\]
Hence, both have identical packing efficiency:
\[
74\%
\]
Step 3: Check each option.
Option (1):
Packing efficiency of hcp and ccp are identical
This is correct.
Option (2):
\[
\text{Packing efficiency of fcc}\gt \text{Packing efficiency of ccp}
\]
This is incorrect because:
\[
fcc = ccp
\]
Option (3):
\[
\text{Packing efficiency of fcc}=\text{Packing efficiency of ccp}
\]
This is correct.
Option (4):
\[
\text{Packing efficiency of hcp}=\text{Packing efficiency of fcc}
\]
This is also correct.
Step 4: Final conclusion.
Hence, the incorrect statement is
\[
\boxed{
\text{Packing efficiency of fcc lattice}\gt
\text{Packing efficiency of ccp lattice}
}
\]