Can I tell if my head unit (cd changer) is a small plug or large plug without taking it out?

[westaussielx470]

I am trying to find a cost effective bluetooth solution and came across the Yaltour unit but apparently there are two plug styles. Being a grumpy old guy I like the stock look of the dash but my factory bluetooth is very selective as to which phone it will let connect. I have had android auto in new vehicles but frankly I never used it but without even an aux input I miss my music streaming.