Can anyone identify this lock?

A previous owner modified my Duster to fit an over-size trunk lock. Unfortunately, the rear housing is broken so I need to replace it. Does anyone know how to identify it? I searched for the numbers stamped on it with no luck. Rather than with a spring clip, it secures with a large bolt to threads that are about 1-1/8" tip to tip. The numbers read ES1143 B1 18594.