"were identical to" is correct and usable in written English.
You can use it to describe two items that are exactly the same. For example, "The two shirts were identical to each other in every way."
So the states embraced the federal plan, noting that many elements were identical to their own.
They built cars that were identical to others of their make but an eighth smaller.
The recruitment procedures were identical to those in experiment 1.
The above data were identical to the literature data [31].
All methods were identical to Experiment 2, with one exception.
Experiment 2a procedures were identical to those of experiment 1.
Exclusion criteria were identical to those for healthy control subjects.
Kinetic experimental procedures were identical to the equilibrium tests.
The shoes were identical to those worn by thousands of other teenagers across the country.
Observation vials were identical to those used for males.
Flight tunnel bioassay conditions were identical to the experiment 1.
