The first used 38 Rimfire & 38 center fire early on , I think the number converted is near 3800 + by Colt, and if you add in the 61 Conversions
upwards to 6000.
Unknown numbers field (gunsmith) conversions, one of the more famous one was the field converted 38 cal. 51 Navy of Buffalo Bill Cody.
As to the test of time, I suppose they were still being used just as we still have old guns today. Cap & Balls were still quite common well
into the early 20th Century.
What they did do is spawn an entire cabin industry resurgency, in the last say 20 + years....
I venture to say Uberti, ASM , Kenny Howell , Dave Anderson, Millington and Walter Kirst have made or converted way more that Colt ever did.
I say they've stood the test of time well into the 21st. Century, and personally I think they will continue for some time.