Usually, yes, but in this case it would be a good idea to verify through the Dell forums or if you can find a CPU support list for the motherboard that came in your Dell, that would be even better.
The reason being, often OEMs like Dell only offer CPU support in the BIOS for CPU models they INTEND to offer with a given model, as they REALLY PREFER to not see people upgrading or replacing hardware, but buying new hardware instead when something goes wrong or performance starts to not keep pace with the demands of software.
If your EXACT Dell model came with an option for the K sku, then it will probably work. If it didn't, then it MIGHT work. Knowing the exact model and submodel, or express service tag number, of your Dell, would help to determine that.
I'd like to say offhand that yes it will work, but too many times we've run into issues where no, it won't, because one of those is a much lower TDP CPU than the other and the motherboard VRM and cooling configuration just might not be good enough to run the higher TDP unlocked SKU.