Yes. Custom roms generally only include the system and kernel, so your base firmware would remain at 4.4.2.
If you go too old though, such as flashing 4.0.4 or 4.1.1 roms, theres no guarantee they wont be a bit buggy. But they should still run nonetheless.
The thing to keep in mind though, is it is ok to flash older roms, kernels and recoveries, but nothing else.