GREP to Find Numbers at End of Story

I want use GREP to do a find to locate any six digit number or just the numeral zero at the end of each story in my InDesign 4 documents.

So far, I have ben able io identify six digit numbers by searching for the following \d{6} But when I add the end of story location marker,  \z\d{6}, no results are returned.

What do I need to do to:

1. get the expression to search for the number at the end of the story

2. amend my expression so that it finds either a six digit number or the numeral zero

Any help on this would be appreciated