Why is this good to know ?? You can often buy "lots" (groups) of locks that are KA cheaper than you can purchase the same number of locks as single units. Not to worry. It is rare that two out of ten will have the same setting order, and even if they do, they will probably have a different "feel" as you pick them.
And, as noted in a previous post, if you purchase locks that can be repinned, you'll have a ready supply of interchangable parts that will enable you to expand your picking skills without buying additional locks. After you're done with one or two, haul out your files and re-key 'em to a different bitting. Fun and good practice.
Don't be afraid to buy locks without keys. The idea is to pick 'em .... Once you get 'em open, remove the core and learn to make a key by hand. Just get a blank of the right type from Home Depot / ACE Hardware or your favorite locksmith. There are plenty of YouTube videos on hand-keying / re-keying a lock. Or, use it for parts. As you progress in the hobby, you'll find that having spare parts on hand is both a time and money saver.
These old carcasses provide a cheap source of pins and springs and cylinders and cores. You'll find plenty of uses for these "spare parts" if you move into making your own challenge locks. You can use existing factory pins to make your own spool / serrated pins. You can practice counter-milling and threading cylinders / plugs and maybe you'll invent some new type of "evil trick".
Anyhow - the message here is that with just a bit of practice in repinning, buying KA locks, no-key locks or just carcasses (cuts / hammered open / damaged / etc) can save you a lot of $$ over the long haul. And, you'll learn a lot about locks along the way ....

Hope this is helpful.