Rackmount dimension question

[Hawaii 5-0]

I piocked up a Hartke 3500 head, tat was originally mounted in a Hartke 2x10 cab. It has two HUGE rack ears, that I will need to cut down in order to fit into a standard 2 space rack. My question is, is the standard 19 inch rack width measured from rail hole to rail hole, or is it the overall, exterior width of the amp head with the rack ears attatched?

PS, I don't have a rack case yet, so I have nothing to measure from for reference.

[Jeff Scott]

End to end of front panel.

[Hawaii 5-0]

That's what I thought, but wanted to confirm before I cut my brackets. Thanks.