The Rieco-Titans on my 2001 Hawk are the c-ring ones. Those came with it. I used them to load the camper onto my older (2001) F150 by bolting them directly to the camper's jack brackets.
When I replaced the F-150 with a 2013 Tundra, I added 1/4" aluminum extension plates. I don't quite remember whether I HAD to have the plates or just wanted additional clearance.
Note: My Hawk has the older jack brackets (the one-piece, 14", five-hole ones) but I believe the jacks should also work with the newer brackets (the two-piece, 13", three-hole ones). (And I see the ones in the manual are the newer style two-piece ones.)
Edited 10/31/22 to add:
Update:
This morning I noticed the manual shows different part numbers for jack brackets for fixed versus c-ring jacks. Does that mean the c-ring jacks ONLY work with the brackets with the c-ring part number? Or will they work with either?
So I called Rieco-Titan Products in Frankfort, Illinois. According to customer service agent 'Sue', the c-ring jacks will work with either bracket. The different part numbers have to do with the type of hardware included with the bracket ordered under those numbers.