Nope, different hardware (faster cpu for one) that isn't available as an upgrade. Careful purchase and sale could see you with an equivalent ultra and even a little profit as many people are less aware about their hardware than you. For instance I got my Ultra at a knockdown price as it was in the sequencer section on ebay. Although technically correct it wasn't the best way to market the sale.
Emu did have an "Ultracize" offer right before the E4 Platinums came out, it was really expensive (between $995 and $1395 after a rebate). It was basically a complete hardware/software upgrade and the cost depended on what you started out with and what options you had.
I guess it'd be obvious once you got a hold of it and booted it up whether it's really been upgraded to an ultra...
no, it was a complete hardware/software upgrade, motherboard swap, 128 voice, CD library, etc.. basically brought your sampler up to E4XT status, that's why it was so expensive