As far as the actual blemishes on the tabs, they must have a very high degree of quality assurance and product integrity, because I couldn't find anything on mine that I would have considered a blemish.
I'm planning on getting some for my boat as well. One problem is that they just look too big for my 16', based on the install instruction. Another issue is that I'll have to move transducer. That will be the 3rd time this season alone. Maybe I'll wait until winter.