According to the installation instructions, replacing the stock floorboard should not require anything other than what is included in the kit. I have included the standard-style installation instructions as an example (full instructions can be found on H-D.com):
INSTALLATION: KIT 50710-04 (FOR
Removing Previously Installed Inserts
1. With the operator footboard in the "up" position, use a
screwdriver to work the rubber insert beads out through
the top of the footboard.
2. Repeat the above steps for the remaining footboard insert.
Installing the New Inserts
1. Apply liquid dishwashing soap to the rubber beads on the
new footboard insert.
2. With the footboard in the "up" position, place the insert
into position on the footboard pan, and hold it firmly in
3. From the underside of the footboard, use a pliers to pull
each rubber isolator into its mating hole in the footboard
pan until the thick collar emerges.
4. Repeat the above steps for the remaining footboard insert.
Hope this is of some assistance!