2 Dollar Bill

 My 2 dollar 1976 bill, has the serial G 28641646 A. How do i know if its COPE o src="https://en.numista.com/forum/images/miniatures/68f7011355d8d.jpg">

And how much is it worth, since it is stamped.

Please add pictures of both sides of your notes correctly, here I recovered the one you posted for this note

68f7011355d8d.jpg (1600×639)

I agree that some clearer description on those different types (COPE / LEPE) would be useful on this page. Maybe @titus17  can add some info?

I assume it is similar to the description on the 1 dollar bill page 1 Dollar (Federal Reserve Note) - United States – Numista

Yours is a COPE.  As discussed here it's very difficult to tell COPE from Conventional by looking at the serial number but not impossible. 

 However the easiest way is to use a table breaking down which is COPE by serial number.  Here's that table for this $2 banknote.  I don't know how to change the Numista pages easily.