Not to disagree or contradict you, but I have to
mention what may be an exception to that in the case of one HP instrument:
There are always exceptions.
Anyway,
http://www.ebay.com/itm/Agilent-HP-Keysight-05480-90013-5480A-5480B-Service…
Is that a different instrument? Did HP/Agilent reuse numbers?
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Will