When Glock first started making their pistols, the metal parts had a black coating. these parts were later called, "Black Parts", due to this coating.
Glock stopped making the black parts around 1992, when they started making the 6 part Upgrade kits, which consisted of the trigger bar, firing pin, firing pin safety, firing pin safety spring, ejector and spring loaded bearing. These upgrade kit parts were no longer black. This made the first made Glock pistols that were made with the black parts more desirable and collectible.
Besides the parts in the 6 part upgrade kits, Glock also made their early locking blocks, slide lock springs, the metal in the older "U" notch pre ban magazines, the metal under the older rear polymer sights, the metal on the slide cover plate, early trigger housing ejectors and the metal in the older NY Trigger Springs with the Leaf spring have the early black coating. It should be noted that the early Glock pistols also had a black serial number plate on the frame, but that is not a replaceable part. Most of the time these parts are over looked or not noticed because they were not the parts in the 1992 6 part upgrade kits and were not switched out for the newer parts by their owners. But if you sent your early Glock pistols to Glock for any kind of repair or maintenance, then Glock most likely switched these parts out as well. But, that is only a guess on my part and not confirmed by me.
Due to the years that have passed since 1992, voluntary upgrade and the turnover in these older pistols to new owners, who sent them off to Glock for whatever reason and their pistol came back minus the black parts, these black parts have been harder to find, especially in good condition. I am sure some people upgraded these parts and simply threw the older black parts away or threw them in a parts drawer, left un-noticed for years. Some may have been lost in fires, sank in a body of water, or kept hidden in a safe since then. For whatever reasons, Glock stopped making these parts almost 20 years ago and they are sought after by serious Glock collectors.
Please enjoy the photo gallery below and check out my store for Glock Black Parts.