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I bought some pieces from BL recently and noticed there were lots of pieces coming with LEGO at the top of them but not at the back (bottom) of them. I am not sure if that is normal among the older sets since I began to play Lego these years. Besides that, the pieces just look identical to the pieces I got from official sets. I am thinking about if I need to contact sellers or ask for refund. Hope you could help me. Here is one example: