It's what happens when you buy random components, occasionally you get lucky ;-)

There's a saying I've heard before: How many 1% resistors can you find in a bag of 5% resistors? None. The 1% resistors were already sorted out and sold as such. I'm not sure how true it is, but if it's true, perhaps a bunch of higher-precision resistors somehow made their ways into a resistor kit not because of random chance, but because they were surplus...

Resistors are so dirt cheap nowadays it's not generally cost effective to make 1% resistors by selecting from a process which makes 5% ones. It's much cheaper to just tune the process so you always get 1% without needing to do the selection. And when you get to higher precisions you have a trimmable design where you adjust the resistance with a laser to get it in spec.

I like to think we’ve gotten so good at making something as basic as a resistor that modern/established manufacturers are so consistent there practically is near-zero tolerance for error.