My employer has one 510(k), that I wrote, for which the predicate had a different classification (ProCode) than the requested/approved classification of the submitted device. I've heard of other similar instances.
There are a number of device types for which more than one ProCode can apply, for FDA legacy reasons. Most of these are exempt, but some require a 510(k).
(In at least one interesting instance involving microscope drapes, it's possible by precedent to classify either as exempt or non-exempt. In the early days when classification decisions were made by the 19 modality committees, two devices were submitted for classification, and they went to separate committees because those committees also have overlapping and vague scope-definitions...and one decided exempt, the other non-exempt, and no one caught the conflict. And, it still exists.)
In my experience, a 510(k) examiner normally considers the predicate as a device, and is willing to accept the proposed ProCode for the submitted device as long as the predicate could have been classified per that ProCode, whether it in fact was classified that way or with another overlapping ProCode.