Viscous Fan Won't Fit

My Pep boys radiator is going on 11 yrs old and this evening I noticed it seeping a little coolant where the core meets the top tank. I dug out the receipt and low and behold they had special ordered this rad for me way back when and they wrote 72 Duster on the order ticket instead of 73. Part number they gave me was in fact a 433526, the one for a 72 duster.

Ain't that a *****, I cut up this damn fan to fit this dopey radiator and now that it needs replacing I can get the correct one for a 73.

I guess if Pep Boys honors their lifetime warranty I can get another 72 one for free. Anybody want to lay odds on whether I can collect on it? I still have the receipt and store number on the order ticket from March 1998.