Where is the serial number on a Mark V head?

[G.I.G.]

So I was filling out the warranty card for my new Mesa Mark V head and realized that I couldn't find the serial number anywhere on the head. I used the serial number from the hang tag but I'd still like to know where it is on the head. I even Googled images of the rear side of the Mark V head and can't seem to see it. Am I missing something glaringly obvious? I saw the serial number on the reverb tank but that's it. Any guidance would be greatly appreciated. Thanks.

 

[SteveO]

On the chassis right by the rectifier tubes.

 

[Gunnski]

Look up...it's at the top of the chassis in the back. I had a lot of trouble finding it too

 

[G.I.G.]

Does it face out (towards the back)? Anyone have a pic by any chance?