Kask elemento

Got a offer on a Kask elemento helmet. The only issue I see is a little dent at one part of the helmet and some minor scratches. From what the seller told me it was used by a pro for a year and did roll off a table once. He even offered to give it to me for 5€ instead of full price, so I can check the helmet and send him the remaining amount once the xray/whatever test shows the helmet is still good. He assured me it’s in a good condition and he wouldn’t sell anything that’s unsafe. He was the one who came up with the idea after I told him I’ll check for a spot in my town to do a xray or some other checkup. Would you go for it or not? Full price would be 70€.

Are there any ways on how to check a helmet? Don’t wanna buy a helmet that could be unsafe.. I’d rather spend full price in that case. 70€ would still be a great deal for a minor dent and some scratches.