GMAT Sentence Correction (SC) | Re: 37(OG VR) Some buildings that were destroyed and heavily

Some buildings that were destroyed and heavily damaged in the earthquake last yearwere constructed in violation of the city's building code.

Hi,
Request the experts to share there feedback.
Is "were" usage in above sentence is correct?
My answer would be yes. "were" and "had been" both are correct usage in the mentioned sentence.
Regards.

Were constructed states a fact/info from the past.
Buildings were[/u] constructed in violation of the city's building code.
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