Yes, they had heeled bullets .451. Some were Bennet primed in copper cases and some were brass with Martin primer.
.44 Colt factory factory were .451, and .44 Remington factory rounds were .448/9. Both had slightly different dimensions. They were largely interchangeable, but not always due to QC issues in making the conversion cylinders, and even the ammo. The Frankford Arsenal cartridges were designed to fit either one 100% of the time. Frontier Army had a lot of 1860 conversions, and a lot of NMA conversions, of which some were .46 rimfire, but some were .44 Martin.
The cartridge on the left is a Frankford Arsenal Bennet primed .44. The Canter is a .44 Colt, and the cartridge on the right is a .44 Remington. Later, some ammunition manufacturers also produced a "one fits all" round, though they were generally labels .44 Colt. I have about a dozen and a half assort makes of .44 conversions rounds, and their specs are all over the map.