Yep. Two alternator options and four pulley options in '65. Alternators were
35A or 40-46A. All the 35A alternators with pulleys, no matter which pulley, were stamped 2098830. 35A service alternator without pulley was 2098525. All the 40-46A alternators with pulleys, no matter which pulley, were stamped 2098850; service unit without pulley was 2098535.
Pulleys were single 2¾" (2444 478 ) or 3" (2095 430 ), double 3" (2095 059 ) or 3½" (2095 662 ). Find the pulley P/N stamped on the front face of the pulley hub.
'65 FPC lists alternator 2098 830 with single pulley 2095 430 as "35A with single pulley, all models",
alternator 2098 850 with 40-46A with double 3" pulley as "all 8-cylinder models with A/C",
alternator 2098 830 with double 3½" pulley as "with 426 cu in Hemispherical engine", and
alternator 2098 850 with single 2¾" pulley as "All models except Imperial".
So yes, 2098 830 w/single pulley as standard equipment, 2098 850 w/single pulley as optional equipment, on your '65 273 car.