I'd speculate the odds of Dell leaving overclocking options in their shipped BIOS versions for a production system at...
pretty much ....well, none.
But, just in case...
Feel free to search your BIOS options, however, as they are normally much more limited than with typical Asus/MSI boards, etc...
SHould not take long to step thru the 5 options with 3-4 sub options in each category....