Yes, the marine cup, too. My Glock smith includes them in all his enhancement jobs, says they cost something like $4 and in his opinion make the gun even more unbreakable.
As for "reasonable cleaning regimen", I would agree with you... my problem is that when I'm shooting a lot, like in the peak of summer/IDPA season, my "reasonable cleaning regimen" gets a bit spotty...
I took a G17 with the enhanced action I've described to a 5-day advanced pistol class at Chapman Academy a few years ago, and fired close to 4000 rounds through it over the week. My car's water pump exploded during that class, and between the hassles of getting it fixed so I could drive home and a SEAL hell-week level beer call after class on Friday, I never got around to cleaning my Glock. I carried it daily for the next week, then shot an IDPA match the following Saturday with it. The gun performed flawlessly, and I have to say I give a good bit of credit to my smith's action job for that.
