Hi Jevi, you have a pair of cool instruments there! Here’s the available info:
Hohner b2b passive with pj pickups, serial number 05115253 was built in 1990 in Korea.
Specs:
Headless bass; body: Californian solid maple; through neck: Californian maple with Indian rosewood fingerboard; 24 nickel silver frets; colour: black, red, silver-metallic; 2 Select designed by EMG; bass humbucker; vol/vol/tone; black hardware, Steinberger, fine-tuning-bridge
B2a with dtuner and emg selects with serial 05114507 was also built in 1990 in Korea.
Specs:
Headless bass; body: Californian solid maple; through neck: Californian maple with ebonol fingerboard; fretless; 2 Select, designed by EMG; bass humbucker; active tone control, on/off; vol/vol/tone: treble/bass; black hardware, Steinberger; Fine-Tuning-Bridge