Ford has never had a posi, and never will, it's a limited slip OR a traction loc
08-09 fx4 were the takeover of the level ii, but didn't get as much stuff, they are a much nicer interior, and have a few other things, come only in supercab, only with the 4.0 (sport can come with 2.3, 3.0, or 4.0)
Honestly, find a 07 level II, they are WAY nicer, and come with a 31 spline 8.8 torsen differential... The only other ford to ever have a torsen stock, I believe was the 2005+ gt500
(torsens I believe were in the 02-07 level II's only)
And I also think the 07 level II's were a Canada only vehicle... I seem to remember they discontinued the fx4 ranger line earlier in the states... 07 was the last year in Canada for the level II for sure...