My first gshock! G-Shock DW-5600rec. My grandfather always wore a G-Shock with a similar trim, and after some searching, I think the DW-5600 is the style that most closely resembles the one
CASIO / カシオ】DW-5600REC-9JF|JOURNAL STANDARD(ジャーナルスタンダード)公式のファッション通販|【21002610000830】- BAYCREW'S STORE