mint error dime

is this a true mint error and if so what would the value be

I'm pretty sure that's what is called a "collar clash" marks.  The collar die has the reeding on it ~ it looks like the edge of the obverse die clashed with the collar die leaving signs of reeding on the outer edge of the obverse die.

It is a true mint-made error coin ~ but it's not worth very much.  There's not a lot of people that collect this type of error.  It's a nice example of the error ~ someone might pay you a few dollars just to have an example of that type of error.