Fleer Laughlin WS question

I'm a bit confused by these. I've been reading auctions lately stating that the blue backs are the 1970 series and the black backs are the 1968 series, yet I thought that the blue backs were 1970, the black(brown) backs were 1971, and the all B&W fronts were 68.
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Working on the following: 1970 Baseball PSA, 1970-1976 Raw, World Series Subsets PSA, 1969 Expansion Teams PSA, Fleer World Series Sets, Texas Rangers Topps Run 1972-1989
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Successful deals to date: thedudeabides,gameusedhoop,golfcollector,tigerdean,treetop,bkritz, CapeMOGuy,WeekendHacker,jeff8877,backbidder,Salinas,milbroco,bbuckner22,VitoCo1972,ddfamf,gemint,K,fatty macs,waltersobchak,dboneesq
Working on the following: 1970 Baseball PSA, 1970-1976 Raw, World Series Subsets PSA, 1969 Expansion Teams PSA, Fleer World Series Sets, Texas Rangers Topps Run 1972-1989
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Successful deals to date: thedudeabides,gameusedhoop,golfcollector,tigerdean,treetop,bkritz, CapeMOGuy,WeekendHacker,jeff8877,backbidder,Salinas,milbroco,bbuckner22,VitoCo1972,ddfamf,gemint,K,fatty macs,waltersobchak,dboneesq
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Always looking for Topps Salesman Samples, pre '51 unopened packs, E90-2, E91a, N690 Kalamazoo Bats, and T204 Square Frame Ramly's