Rangers have never had factory keypad entry, so there is no code printed anywhere on the truck. If yours has a keypad, then it is a stick on accessory that works like a keyfob (wireless). The 5-digit code came with the accessory keypad, not with the truck. Unless you can get the code from the previous owner, you are out of luck.
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles
2003 XLT 2.3L M5OD-R1 reg cab beater, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid