hpi did do orange anodised version mate, and they also did do an orange main chassis as well,
but it could be a km,
there are a few tell tale signs if he has more detailed pics, hpi main chassis has an extra hole offset to one side about a third to halfway along the chassis from the front on the underside, this is a location hole for a plastic stub on underside of the battery box, only hpi had the stub and hole, unless km have change recently that is,
also hpi has there name embossed on the battery box lid,
shocks also have different knurling on the spring prload adjusters on hpi v km,
there are a few subtle differences, but the dude coulda just built a bitsa with an hpi chassis and is trying to pass it off as hpi genuine,
if yer in doubt though, don't buy it

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people do try and pass off km's and rovans as hpi all the time, a friend of mine bought one a few years ago , sold as gen hpi, brought it to me to have a look over it, first glance could tell it was a km, it was bought for his grandson who was with hime when he went to pick it up,
so the seller knew he was ripping off a 14 year old kid at the time,
i ended up building him a proper one from spares with a few upgrades etc,
oh dear, i'm off on a tangent with a long post again

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anyways, it was a respected member off a different forum that sold him the thing, (don't remember the blokes name now though),
just be very wary when ya but owt used, there are some good deals out there, but also lots of crap on the market as well,