Sure - a highly verbal extroverted gifted child might be more easily noticed than a more introverted child with say, mathematical gifts.

This is one of the reasons, BTW, I had outside testing for DS6. He is the quiet, more mathy child. Although his K teacher noticed his gifts, she is an excellent and experienced teacher, who really made it a point to know each child in her classroom. Without testing, he would have faced a new teacher every year, who may have taken months to notice he is a bit different - when he finally decided to "let her/him" into his world (resulting in much wasted time every year).