After doing a little more research, I think it's doable. If the weghts on the production list are close, a 75b is just under 35 oz. A J-Point is 0.5 oz. By the time you remove the sights and mill the slide, I bet you've already made weight for the J-Point. If not, a plastic guide rod and some light weight grips should be enough to get under the weight requirement.
I might just have to do this.