They're still out there; there are a number of pretty decent sources: Numrich/Gun Parts, Liberty Tree and Apex Gun Parts are the ones that I've sourced from so far. You might, for example, have to order the 2 components of the 2-piece firing pin from 2 different suppliers; in my case, Numrich had the right rear, but no front, but Apex had a complete set, but it was Egyptian contract parts, so the rear was useless to me, but I needed their front because Numrich was out of stock.
Consumables (springs mostly) seem to be available. I'd recommend judiciously order some spare parts (firing pins, firing pin springs, perhaps some of the other springs) but these things are pretty solidly built, so I don't think there's a huge amount to worry about in normal use with decent ammunition, and cleaning and lubing.
Best, Jon