As stated already, the answer is "yes, 100% legal".
IMHO, you owe it to yourself to install the comp hammer, it's probably the best $70 you'll ever spend and easier to install than you may think. Add a 15lb hammer-spring and reduced-power firing pin spring and it'll set off anything and be totally amazing... Though, drop another $20 for an extended firing-pin and you can go down to a 13lb hammer-spring, still with 100% reliability, just with a noticeably even better hard-to-believe-it's-that-good DA pull too.