I've considered it, but never really took the time to do it. The 301 springs have been talked about quite a bit, and from what I gathered Buck considers it more of a preference than a defect. That's not directly from Buck, but it sounded like guys have inquired about the issue already. Since it's not really expensive I just chalked it up as a loss.
Actually, having grown up in that era, and being an old fart, I can attest that among a lot of the old guys that I knew growing up, softer springs were a preference. When I was 12 years old, we had a scout master who was a retired marine who taught us young scouts to never have a knife that you have to fight with. And that at times, your hands may be wet, or cold, or both, and that will hinder your ability to open a stiffly sprung knife. This from a guy who saw some of the worst action on Guadalcanal and Saipan.
My own grandfather, a working waterman on the Chesapeake Bay, carried an old Hen and Rooster that had an action smooth as soft butter and very lightly sprung. As grizzled an old cob that he was, he seemed to like a softer sprung knife. When he was getting on in years and lamenting that he couldn't get another real Bertram made Hen and Rooster, I asked him about the few 'other' pocket knives in his drawer. He told me he didn't like them, even though they had been gifts over the years, because they were too hard to open under less than ideal conditions. This from a man who made his living crabbing in the summer and oystering in the winter out on the water in any weather.
With a slip joint knife, once you open it, any cutting pressure on the blade is in a direction that will keep the blade open. This is how friction folders work. When slip joints came out, the main purpose was to keep the blade from opening in the pocket. Before slip joints, people just used large single blade friction folders like Opinels with no locking ring, Sardinian resolza's that were very typical of knives of the 16th and 17th centuries. To this day, I very frequently carry a Essolza, and the complete lack of any back spring at all is no matter if the knife is used right.
Some of my favorite pocket knives that have no back spring at all;
The Opinel has the blade pivot adjusted to be fairly snug, and I very rarely ever use the lock. JUst pull open, cut what needs to be cut, and push closed. The same for the middle knife, the Japanese higonokami. The Resolza has been made for hundreds of years, and is a very traditional knife in the Islands culture. JUut a simple but stylish friction folder that cuts all sorts of things. The Japanese higonokami is also a strait friction folder that I have the pivot peened snug, so it won't just fall open in my pocket. They both have external pivot pins so if they get a little loose, they can be peened sung in a few seconds.
I have become so used to the friction folders, that I don't mind a very light spring at all.