Any chance I could fit a 2001 (o-ring) oil cooler line to my non o-ring engine by swapping the nipples?  I bought a used pair of lines on ebay to replace my badly leaking one.  Their compatibility computer said it was good.  It came with nipples on the cooler side/ends that might fit my cooler.   If that nipple fits on the engine end I should be good.  Of course getting the present nipple out of the cooler may be a bear.  Any idea?
   The seller said he would take it back but if I can make it work then all the better. 

Yes, the threads in the cases are the same between A-N and o-ring equipped models.

Threads in the OEM coolers are the same as well.

For removing fittings from the cooler, one wrench on the fitting, one wrench on the cooler.
DO NOT react ANY torque by holding the cooler body.

Thanks, it fit and is not leaking.