can I "re" download ML?

I bought ML on the first day of realease and waited to install it. I am glad I did since there were problems with in install. I am ready to install it over Lion on my MBP, but I want to most recent version with bug fixes. I have the .dmg image of the first version. I have my MAC backed up, but if the original version of ML crashes my MAC I can't afford the downtime.

Any thoughts. I can't click download while logged into the app store and get ML agin. It won't let me do it.

Should I delete it from my HD?

Cheers