Front fork question

[TrapperAH1G]

'01 Nomad VN1500L. Left fork leaking badly, going to rebuild. Popped the caps off the top of the forks and found what appears to be a "nut" with a hex head (see pics). Looks like a smaller hex head at the bottom of a larger hex head opening. Surprised me, haven't seen this before.

Is there a special tool required for this or can you just use the large hex opening? My understanding from the manual is this is a regular type fork, not a cartridge type?

Thanks