That does not mean the ship itself was used in a destructive test. Do not assume the word 'target' automatically mean a destructive test.
The presence of radar reflectors can exclude destructive testing. They can be used to verify the efficacy of whatever radar seeker assembly in question. If anything, the test designers would know that the weapon determine the testing regime. Destructive testing give physical forensic data in the event of a failed test and forensic data is the data of last resort. Keep in mind that in a ship versus missile scenario, and it does not matter if the weapon is a missile or a descending warhead, if the missile failed by even just one meter, the ship win. So if the test fail and we must resort to forensic data to find out why the test fail, we want minimum contaminant data such as weather or countermeasures.
In the 'real world', target maneuverability, weather or countermeasures are variables that are outside of the attacker's control, therefore it would be wise to conduct comprehensive 'rigged' tests where these variables are gradually introduced. The presence of radar reflectors is a sign of one of these 'rigged' tests. The reflectors are necessary to simulate the large and flat deck of an aircraft carrier. Over time, assuming the chief test designer is a wise one, the reflectors get smaller and the variables get more complex and intensifies. Reducing this radar signature does not imply the carrier is getting smaller but such a 'rigged' test would increase stress on the radar to maintain target lock in the presence of those variables. If the destructive test fail, as in the missile or warhead missed, and if the system has proved itself capable of handling variables such as a cloudy day, chaff, EM jamming, or ship maneuvers, then the forensic data will lead us to different avenues in the investigation.
So where are the sources that said such destructive testings were completed and the results were successful, as in meeting all customer's requirements?