I wanted the 3 dot for my PM major and went ahead and ordered the Novaks from Brownells. When I took the gun to my 'smith he asked me why I was swapping and how much I paid for the replacements. Long story short my smith drilled the existing sights and installed the white dots I wanted for $35! I couldn't tell them apart from the Novak sights when it was done!
Get a cost on modifying your existing sights first before you spend the money on new ones; it could save you both hassle and money.