Steering gear question- 97/98 different than 99-01?

So I'm running down parts and prices to finally deal with my sloppy steering. I was floored when I started pricing new and rebuilt gearboxes(as high as $750!! for a stock XJ?!). Started chasing part numbers and prices, and noticed that Advance (Cardone rebuilt), and Autozone (Atsco rebuilt) list a single box for XJs 97-01, but NAPA shows a different box for the 97/98 (also the box used by some ZJs, Dakotas, etc) for $189 + $223 core charge, while the gear for 99-01s is $114 + $84. Half as much money for a newer case? WTH?

So, I dig a little bit, and see the same pitman arm, input and output shaft sizes, same lines, same mounting hardware, etc etc regardless of which year, 97+. So is there an actual difference between the two boxes? Is there some physical difference that would make it impossible for me to use the newer gearbox? For what they want for the rebuilt "97" gear, I could buy a modified PSC box, or a NIB AGR unit.

I don't see why everyone else would offer a single part number, and NAPA would offer two, unless there's an error, or the boxes are interchangeable. Anyone know exactly what's going on with this? I'll probably have to spec order the box and hoses, so I want to make sure I don't buy a box I can't use. I could use a little insight here.

I guess we've got some NAPA folks here too- if anyone can compare the two directly, that would be a real bonus. Looking at application charts atm- the 8133 box shows as being used only on 96-98 Jeeps, whereas the cheaper box appears on S10/S15 vehicles, Jeeps, Caddies and Pontiacs, from 82-01, with the exception being no listed apps from 96-98. Hmmmm

NAPA
97/98 p/n
NSP 88278133

Listed 99-01 p/n
NSP 88278076

Autozone p/n
Atsco 7525

Advance
Cardone 27-7582

And yes, I've read numerous threads on rebuilding the sag boxes, Dakota/Durango swaps (some of which are the -8133, same as the XJs), but I don't have the time nor desire to rebuild, and I don't want to get stuck with the core charge, have to modify/buy a new spacer, etc. Looking for zero tweaking at this point.

http://larescorp.com/catalogs/catalog011608.pdf

http://cgi.ebay.com/ebaymotors/1980...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Larescorp. sells the same box 84-01 XJ and until 98 grand.