UCLA Law,
You may want to research this section of the Forum, as I believe this has been a recent item of discussion. I believe the answer is "yes" - you can replace the hammer with a different part number. 3914/3913, 6904/6906 pistols, along with the other compact versions have this semi-bobbed hammer arrangement for a reason. It promotes access to the pistol when concealed. Even though these pistols have serrations on the hammer, the DA mode makes thumbing unnecessary, as does the decocking lever. As one who still has a couple of SA 1911's I can understand the emotional "need" of a conventional hammer. But the reality is, from a practical standpoint, you'll be just fine....