Specific to your question, no.
However for what it's worth, once boxed, front and rear Alfetta bumpers (with overriders) had the following dimensions/weight:
160cm x50 cm x 18cm - 15kg
Therefore your weight estimate for one bumper seems closer to true. However how and with what they are packaged (if anything) is not trivial to the overall dimensions and weight. Actual weight might not come into play here as at these sizes, dimensional weight will probably be the determining factor.
However for what it's worth, once boxed, front and rear Alfetta bumpers (with overriders) had the following dimensions/weight:
160cm x50 cm x 18cm - 15kg
Therefore your weight estimate for one bumper seems closer to true. However how and with what they are packaged (if anything) is not trivial to the overall dimensions and weight. Actual weight might not come into play here as at these sizes, dimensional weight will probably be the determining factor.
