Did he tell you they were covered by manufacturer's warranty? You can't expect him to be involved if some problem should arise in the future within the warranty period.
Some manufacturers only honor the warranty for the initial purchaser. They work with their dealers to resolve the problem. IMHO if something is DOA, you get a full refund and seller pays shipping both ways. Warranty or not.
Personally, I would not buy something at this price level without some dealer involvement, even if he is selling it on consignment for someone, you have an assurance that everything is in working order. It's worth the extra 20% for the peace of mind.
Better yet, if possible, buy things that are within driving distance so you can check them out and drive them home yourself. Also avoid any possible shipping damage.