Hi Richard,
The only place I know of where you can get the label is in the
snippet. The label is just another identifier. The AdWords help page on
Standard Remarketing says:
You can leave the Conversion Label field blank if there is no google_conversion_label in the code box.
This leads me to believe that there isn't
always a label in the snippet. If you just take whatever snippet is generated and
add it to your page, you'll be on your way to tracking conversions.
Cheers,
Nadine, AdWords API Team