By sheer luck, while training my nuzlocke team on Emerald, I encountered a Spinda on Route 113. It had a half spot on each ear, and a long spot in the middle of its face. I ran from it and moved on. I then encountered another Spinda, WITH THE EXACT SAME MARKINGS. I'm not even kidding. Same gender too (Female). I lauged, that was awesome xD
This post is pretty useless, I just wanted to share the fact that NOT EVERY SPINDA IS DIFFERENT!