Joe - Glad you joined.
On the frame, you don't really have to figure out what you have. If everything bolted onto it you are in good shape. For instance, I put 1996 fuel tanks in my 1985 and they fit perfectly.
As for the "HPB37778", I'm going to guess that's somehow related to the VIN of the truck from which the frame came.
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