edit - I find this very hard to believe, especially after the guys at Synapse say it is not one of their intercoolers
who did you buy from? If you bought from Synapse they should have a record of the transaction. to my knowledge synapse never made endtanks with mounts like the one pictured. also Garrett cores have a black rectangular stamp (which can wear off over time) on them as well as some chicken-scratch engraved (either both on the top or both on the bottom of the core) <- care to verify?