The level of the truck, meaning base, XL, XLT, or Lariat had nothing to do with A/C since it was an option - with one exception. At least in '85 the Explorer Package D came with A/C. But none of the other trucks.
The driver's side is easy to put vents on, just by changing out the instrument bezel. But they won't connect to anything unless the rest of the HVAC duct work is in the dash.
However, if there aren't vents on the passenger's side then then truck probably didn't come from the factory with A/C. I say "probably" as it is possible someone swapped a non-A/C dash in.
Instead, I'll bet your truck came with dealer-installed A/C. There were several different models of that, but some of them had under-dash vents.
The real question is what is under the hood. If you gave us a shot of the area of the firewall on the passenger's side, from the engine out to the hood hinge, we might be able to tell you what you have. That's 'cause the firewall for a factory A/C truck is different from a non-A/C truck. So the A/C plenum for dealer-installed air is different from factory air. The illustration below shows a factory A/C system:
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI