My iPad when check on apple support said Purchase Date: April 1, 1978
Hi, when I check on mysupport.apple.com, I see that my device Purchase Date is April 1, 1978. Is this abnormal?
Well, the date shown is clearly incorrect - which is unlikely to be disputed by Apple. Unless you have immediate reason to be concerned, you might just choose to ignore the problem.
In the event of ever having to make a warranty claim, you would always be well advised to ensure that your original purchase receipt/invoice is available to prove device ownership and/or warranty entitlement.