Danny - I started looking for part numbers in the Master Parts Catalog and finally realized that it isn't simple. There are lots of variables. However, what I've done is to put the whole section on refrigerant lines from the MPC on the website here: Documentation/HVAC/HVAC Systems and then the Refrigerant Lines PN tab.
If you look through that document, which you can print and take to your shop, you'll see several things. First, there are part numbers for the lines, but I kind of doubt you can find the lines anymore. But, there are supposedly lengths shown for each line as well as the fittings needed.
However, I call your attention to the bottom of Page 8 where it says that 1980 - 82 trucks built in the Twin Cities or Norfolk plants take a different hose than trucks built in other plants. That tells me those two plants were using different components than all the other plants. So I wonder if your truck is one of those, which might explain why the shop is having a hard time finding the right parts.
I hope that helps.
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