Hambo, without the plates you will not get a definitive answer to it's authenticity.

Ask the seller to send you photos of all 3 plates so you can determine it is a genuine Sandman.
You may also need body verification, but get the plate details first and we'll help you out.

Also use our quick ID guide to give you a broadscope;
http://www.mysandman.com.au/files/gu...an%20guide.pdf