All screws are 1.5" (38.1mm) long. Some manufacturers supply pickup screws with their pickups, some do not...
I had the same experience as Josh Dyson. The screws were a little longer (the reason I bought them, based on a warning that the stock screws might not be long enough for the Bartolini pickups), but also a little bigger than the originals. Wanting a change to black screws, but not wanting to enlarge either the pickup covers of the pre-drilled holes in the bass, I stayed with the stock screws, which worked just fine on my 2002 MIM Jazz bass.
Different from Originals
By Bob Hermann from on 4/27/2017
There may be different sizes when it comes to these, so take this with a grain of salt, but they were a bit thicker than the screws in my MIM Jazz Bass. Too thick to work with stock pickup covers.