I work in the Auto Industry, We get super low balled everyday. Sometimes just sometimes tho it works out in the customers favor for some reason or another. Old age unit or Volume bonus within reach etc. Nothing wrong with a low offer as long as it is polite. For what its worth PM'ing it is usuall the best way to go. At least then they understand you are not trying to insult them.
VERY VERY sick gun. GLWS you will get all the money for that one!