The only '68 run guitar center ever did with a 60's neck were the triburst ones from 2006 (2nd pic). Believe me, if you're not sure if your neck is a 60's, than it is a 60's. The 50's neck '68's have always been undeniably chunky. he you have the '57's which are very chunky-baseball bat feel.
a '57 Cloud 9
A GC '68 with the 60's neck
Regular '68's
Regular 'new' Customs