the retro fittings are more for ease of use and to let whoever services the car in the future know that it is a converted ac system. more important is replacing the o-rings and drier, flushing the system then using a compatible oil prior to the initial charge. once you've done all that then you would want the appropriate fittings anyway right?
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"