General Nikon astrophotography question

[RobertYork]

I've been doing reading online, and when it comes to Nikon, the amount of information I've found on astrophotography is very limited. However, one thing I found interesting was some information on some built in noise reduction that was being done on long exposures, and this 'Mode 3' trick to get raw data from a Nikon. Is this still a concern or issue at all?

 

I ask because I recently found my nice little Sony a6000 (and all other new Sonys) have a nice star-eater feature, where they do digital low pass filtering on any bulb photographs, which effectively erases stars, thinking they're single pixel noise. I ran into this when doing some first light test and could not for the life of me figure out how M3 had simply vanished from the sky. It sounded like what this Nikon issue was. I wanted to be sure that's no longer an issue, if I am going to consider another brand of camera.