How to access non-screw outside plumbing access panel

[Wolverine]

I have received permission to open this panel- but haven't seen one of these without a flathead (or phillips)...this access point is flush like a nailhead.

Any suggestions on how to open this?

Plan to use a putty knife and hammer to unseal the years of outdoor paint.

[Jerry Simon]

Get permission to pry it open (looks like someone already did such along the bottom).  May very well be a nail.

[Wolverine]

Thanks Jerry.  

Upon closer inspection the edges show some sort of caulk sealant so I'm guessing you're right- it is a nail.