help age this 870 for me

[wheelie]

My 82 yr old father recently passed down his 16 gauge remington wingmaster that my mom bought new for him AROUND 50 yrs ago . It was his baby and he can't remember how old it is . can anyone help me .... The barrel code on the left side of the barrel is a 3 digit ??? DBH and the serial no. on the receiver is 428048W . Any help would be appreciated thans