This page describes four Gibson flat top acoustics, the J40, J45, J50 and J55 - though the J50 is not pictured.
UK prices (1981) were as follow: J40, £789; J45, J50 and J55, £829.
$2500
$1680
$4995
$3795
$1995
$79
$1999
$4000
$1726
$35
$795
$4200
$295
$795
$1695
$2695
$4495
$1760
$6300