Apparently they were both design by Christian Tresser: http://gwarizm.com/2016/07/17/spiridon-dada-a-tribute-to-a-cult-classic/
I picked up the Spiridons that released last year because they reminded me of a pair of Air GXs I played in, only to later find out they were both also designed by...
I have no reason to suspect they're fake other than I bought them on ebay for $15 under retail from a seller with a full size run in multiples. They also smell like shoe polish, which is kind of weird, but maybe normal for these.