Green’s Dictionary of Slang

gecko n.

In phrases

have a gecko at (v.) [play on dekko v. + ? gander n.³ ]

(US) to take a look at, to glance at.

2001

Kevin ‘The wild card’ posting 7 Nov. at abc.net forum 🌐 And in the opposite corner is Beazley. Let’s have a gecko at Kimbo. He obviously stood up for rights of the asylum seekers didn’t he. No he didn’t.