I own a few self-loaders that bear the mark of the prancing pony, but they're not really my first love. When you cut me, I bleed blue and white, not blue and gold, so I was completely unaware that Colt's has added a serial number lookup service at their website.
For instance, I plug in the number on my older 1908 Vest Pocket, and it tells me that it was made in 1909, whereas the newer one dates to 1916. This saves looking for that tiny little blue booklet that always goes missing.
A factory letter including data on to whom the gun was shipped is still $75-$100, though. A factory letter from Smith is still $50. This is because Colt collectors are Fancy Dan rich dudes and Smiths are the workingman's collectibles. (If the workingman in question is a $75/hr union employee.)
(The post title comes from the time a guy brought in a Colt for repairs that looked like it had come up off a U-boat wreck. The gunsmith expressed doubts that it was worth the time. "But Shannon!" I said "It's got a prancing pony on it!"
"That's not a prancing pony," retorted Shannon, "That's a dead horse.")