451's are good for recording, but they are a little bright. These are fixed cardioid caps - new sets go for about $1K. Used they're probably worth $700 or so - maybe a little more.
You might do better to pick up an older pair of 451E or 451EB instead - these are modular and omni, card and hyper caps were made for them. You can often get older 451's for 300 apiece, sometimes even less.
Dirk