If you purchase the kit that has the PERC with the blanking plate, you will probably get the relevant leads with the card (although may be wise to confirm prior to order).
The snag I've found when I've ordered those kits is that I've never found one with a battery for a sensible price. Batteries can be purchased seperately - the battery connector is present on cards shipped without batteries.
I would highly recommend you use the battery - without the card defaults to disable write caching for good reason, and this can cause a severe penalty under demanding workloads. (Write caching allows pc to dump data to the PERC, then the PERC writes it to the drives in it's own time - if data is written to a non battery backed cache and the power is pulled, it may be partially written or even not written at all to the drives).
There are PERC cards intended to be fitted to Dell rackmount servers that come on trays and don't have the blanking plate. These cards are identical to the regular ones and have the screwholes for the blanking plates, but without the plate, they can work their way loose of the PCI-E socket which will not be nice in operation.
Once your done, if they are Dell servers, setup OMSA if not already done, if not in a supported Dell server and running Windows, then load the LSI Megaraid Utility (can be found on driver pages for some Dell servers).