Thanks.
The head diameter may differ even visibly slightly from manufacturer to manufacturer, but shouldn't concern you too much.
The thread pitch is determined by the screw diameter type. A 2 mm self tapper for plastic will always have the same pitch, regardless of manufacturer or year.
Don't mix up M2 and 2 mm, like so many shops do unfortunately.
The "M" stands for ISO metric machine screw thread. Machine screws with their fine pitch are not meant for threading into plastic threads, they are only meant to screw into metal threads. Still, you CAN try machine screws at your own risk.
If you've got trouble finding suitable 2.4 mm screws (do these exist?), you might get away using 3 mm screws IF you slightly enlarge the plastic thread hole to something like, let's say, 2.5 mm, beforehand. A fine pin vise helps with carefully drilling into plastic. Also make sure the head will still fit.
I had to replace all the case screws on the bottom of my Turbo Duo with 3 mm Tamiya screws, since the previous owner already replaced the original screws with some others of the wrong type, and had stripped the holes due to repeated assembly. With the screws I chose, I was able to cure the problem.