Absolutely a lot of gun to gun variation.
2000 snaps as recommended by SIG Sauer chief armorer did sweet bugger all for the trigger pull of a P220. A visit to Teddy Jacobsen helped a lot.
A friend's home market P220 did not need help.
1980 Browning BDA 45 (Sig P220),, casual use for about a decade, (maybe 2000+ rounds) no smith work, no dryfire practice and damn little DA use, DA pull weight dropped a significant amount, seems like nearly half, but I'm sure not quite that much...
Every gun is going to be different about this, some break in well get noticeably smoother, some never seem to until the visit a smith.
I don't see what you've got to lose by dry firing, cycling the action a lot of times, besides some time. The exercise strengthening your trigger finger (and grip, and hands overall) certianly isn't going to waste, and if the trigger improves, then, YAY!! go play with live ammo and have fun! And, if it doesn't, it can still go to the smith for tuning to your satisfaction.
And yes, Colt DA's are notorious for "stacking".