Today while I was fixing an issue at TeamMentor, I wanted to play around with the URL manipulation.
I tried to remove all the dashes (-) from the URL GUID to see what would be the behavior. And I was able to see the same article without any side effect (by side-effect I mean that the result was the same).
I was wondering if the fact of removing the dashes from a given GUID should cause any damage to the integrity of that GUID. I did a quick search on internet and I found this thread at StackOverflow called “Is good idea to remove dash from a GUID?”
The short answer given to this question is that the integrity or uniqueness of the GUID is guaranteed even after removing the dash. Also in this thread, some of the folks state that dash are added for readability purposes. The anatomy of a GUID is described here
In fact by reading this thread at StackOverflow, I discovered that using .Net you can generate a GUID without the dashes. I used PowerShell to give it a try.
TeamMentor Development and Testing 
Good article about the test of command injection vulnerabilities