If you are strictly looking at used hitches I would look for one made specifically for the Ford puck system, which I know is a different pattern than Ram. May be hard to find though. Otherwise, you can get an adapter which attaches to the pucks and allows the use of just about any hitch. Just make sure the hitch has plenty of height adjustment because some of the adapters can raise the hitch height by as much as 3 inches. Your new Ford already sits taller and the added height can really make your fifth wheel sit nose high.
JimT
2020 Jayco Pinnacle 32RLTS, 2020 Ford F350, Platinum, 6.7 diesel, 4X4, CCLB, SRW, 12,400 GVWR