Yes.
Here's what you're looking at: 45ACP, according to industry standard, diameter of the bullet should be .451 for anything with a jacket. Lead is usually cast to .452. That's a standard practice, too - some guys cast lead the same diameter of the jacketed bullet, but more often than not, you'll see the cast bullets one thousandth of an inch larger.
Now... the 45 Colt cartridge, often called Long Colt, was invented a looooong time ago - Custer's boys were carrying Colt Single Action Army revolvers in .45 Colt last time they were seen alive.
Back in those days, things weren't quite so well standardized as they are today. Many of those Colts - and other firearms manufactured for the 45 Colt cartridge have larger bores. Look CAREFULLY when you buy .45 cast bullets. The ones cast for the older firearms chambered for 45 Colt needs a .454 diameter bullet. Modern 45 Colts (like Ruger's New Model Blackhawk) have .451 bores.
Those bullets are far less common than .451 or .452 bullets. Casters who sell to people who shoot older 45 Colts (like the cowboy bunch, SASS shooters) offer bullets that are identical - but in two sizes: .452 and .454.
Arms made in the early 20th Century were usually .451 - like ALL Colt M1911 auto pistols. The older Colts, and some imported replicas have bigger bores.
If you have, say, an Italian replica gun made in the 1950's, who knows? Slug the bore and find out.
