Well, no real proof I guess, but here is the story. I got a dedicated MKII. I wanted it to work as nice as possible so I went about replacing all the buttons and joys to make it function like new. I could tell the ones in there were stock b/c stickers were still in place, over where they sticks were installed. In fact, I remember thinking, man maybe I should keep the OEMs to keep it "authentic" and just swap out the micro switches. Then I just decided to go ahead and do it and keep the OEM sticks.
I noticed they looked a little different and felt TOTALY different. When I got the heavy spring installed, they felt about the same, but still, different sticks (from what I recall).
Later I got a dedicated MK3 (not UMK3, but regular MK3) and same sticks as MKII. Don't know what to say other than, my memory may be wrong (I have had and worked on dozens of machines since then), but maybe Comps were built different then? Companies do make changes to their designs right?
Either way, a Comp is a perfect replacement (with the heavy spring) as far as feel goes, so go for it. Just hang onto the original sticks if you want.
If anyone still cares about this in a few months, I'll post my pics when I can. Hell, I might even make an entry in the Wiki so this info will stay forever. I should have done it when I took all those pictures of the LS-30s, but I totally forgot and that post is probably gone by now.