It will help but not cure the issue. More grease will squeeze out than go into the bearing.
One guy presses out bearing and carefully cut a slot into it 3mm x 8mm or so then drilled and taped the intersecting area. After putting in the grease fitting he chamfered the inside area with a dremel.
We compared notes...Our kids both ran 30+ Harescrambles/events. I replaced the bearings around June (after the slop season) and I also greased them once before June and in September after replacing them, they looked great in September. We sold the bike in late November and the owner checked them and said the grease was just getting dirty but they are still tight.
Our friend's with the grease fitting mod never had them apart but had to replace them in late september as they started to wear.
IMO I would rather take them apart and clean them then go through the hassle of drilling, cutting etc. I found most of the wear to start on the sleeves. Grease looked good but you could still see a few thousands wear on the sleevs.
Long reply but we are on our 5th and Last RM80/85 and I am a maintainence guru..