They put grease in the sockets, and maybe it is hard now and looks used.
Anyway, that is a
1980 only harness:
APPLICATION PART NUMBER ENGINEERING #
80 F100/350(99) 100/350(99)-- - w/rear w/rear bumper * EOTZ 13A409-D EOTB 13A409-DC,DD,DE
Gary, AKA "Gary fellow":
Profile
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