Ok First off I am a consumer like you , not an expert so I just am passing along info I have figured out because I have real pink pony from ralph lauren, and I bought a fake from a schister on ebay and I noted the following differences....  Be aware of sellers with big lots these could be fake from china etc.  If you are buying a sweatshirt ask the seller if the zipper puller says polo engraved in the puller. It will also have a pink tab puller. If is does not it is counterfit. The other way to tell is if the tags on the inside sewn in are wrinkled and look like they were just sewn in after manufacture. The tags, could in addition have frays and crooked stitch. This is a tall tale sign that these are fakes. Lastly ask to see a close up of the pink pony design. If you see any fading or not clear crisp design this is also fake. There are a lot of counterfiters out there was one that sold one to me and I got my money back because I prooved that it was FAKE to the seller. Don't take this lying down. You can report all counterfiters to the security center. Take action on these people and get them booted off of EBAY. The powers that be at ebay strictly go off consumer complaints,  they have no way check quality or authenticy of merchandise. If you don't do anything it will continue.....