how do u tell a fake

[sawdust]

hi i broght duo chips off www.modzone.com and all worked 100%
and there is a link off the duo site for this company. they look the same as what is on the duo site but other sites the same chip looks diffrent. On the ones i have seen the duo mark in on the black part of the chip but others on the net have the mark on the top corner of the blue part of the chip so which ones are the real thing??