There are 2 different hoses, one for variable power assist steering, and one if you don't have that option. The part listing I have shows 26079289 as being an inlet hose. Isn't the pressure line the outlet? Perhaps that is where the dealership made the error. For what it is worth, my parts list shows:
26079289 - inlet, w/ variable power assist steering
26079288 - inlet, w/o variable power assist steering
Just went through this with my wifes 2000 Lesabre.
The RPO code for the magnetic assist steering is NV8 or NV7.
GM part number #25727229 w/o mag assist and Part # 25727230 with mag assist. This is the part numbers for the return line with the cooler that runs along the right side of the frame then along the front rail and sits between the rad and engine then loops around and goes back the same way it came along the right frame rail. ***NOTE*** The new line will run along the right frame rail and then along front rail but then will continue from cooler to the LEFT frame rail and back to the rack and pinion. GM has a service bulletin from late 1999 on this.
The new line will not look the same as what is on your car. The after market Edelman number is 92263 for the return line w/o mag assist and Edelman #92264 with mag assist.
I paid $100.37 for both high pressure and the return lines taxes in.
Hope this helps.