I know what your saying, but out of all of the ones I have ever seen, be it in a dozer, loader, excavator, etc, ((and brand seems to make no difference)) simply collapsing the spring to remove it from the track frame really isn't the problem. Like you say, it can be collapsed without using the nut, but the problem is that with the through bolt, 99.99999% of them are corroded to the point that the threads were gone, beat up until the threads weren't repairable, or any other kind of 'damaged' you can think of.
That's why I said what I did about buying a used one. If the threads are messed up, it doesn't matter if you can compress it and remove it with no problem, the problem is that there is no way to safely recompress it, and hold it in that state long enough to install it into the frame.
Not to mention your still putting a spring that has seen a hard life back into a spot where abuse is going to continue to occure. Given the cost to buy used and get it shipped, and the cost to buy a new one, all rolled in with ll of the work necessary to break a track, cut a broken spring out, etc, etc, etc, to me it's just not worth taking the chance on a used one unless there is nothing else available at all.
That's the advice I'd give any of my customers and I'll stick by it in 99.999% of the circumstances I can think of.