If this was posted in the wrong location it will be moved, no worries.
According to the MPC, and assuming that the Ranchero aligns with Fairlane/Torino (safe assumption IMO), you are looking for a C5OZ-8146-A. It is listed as "one-piece type-steel". Based on that it appears the part you listed has a likelihood of being correct. Since the description explicitly includes the 68 Ranchero, you have eBay buyer protection if you get it and it does not fit. But you should check it right away and not wait weeks/months.
The previous statement would be for factory AC - there is no listing here for the dealer "hang-on" type. I need to look for that in the kit section.