The major portion of advertizing by ABU Garcia in the USA focussed upon
Ambassadeur (1952 +) see below
500 Series Half Closed Face reels
This represents only some of these fine reels, originally made popular by match fishermen in UK and then a world wide storm of appreciation of the strength, utility and reliability of these reels.
The series comprises 501, 503, 505, 506, 506m, 507, 508 in the original all metal classic period (50's to 70's)
The 520 here was especially marketed for the USA and was identical except for different badging.
The 507 and 508 are identical except sporting left hand and right hand winding ability.
More detail found on main page here