37mm AA - Did they use tracer ammunition?

[[TWB]80hd]

I always assumed this was a resounding 'yes' as trying to hit a fast moving target without a means to see where your round was going would be very difficult, but it seems as if in-game medium AA is tracer-free.

 

Is this historical? 

[unreasonable]

I am fairly sure that tracers could be used - I seem to recall accounts of RAF night raids where the cannon tracers up to medium altitude are clearly visible. But tracers are not a very good way of adjusting aim against aircraft, slaving guns to a fire control director is much better.  This does not work so well at night unless your director is radar assisted.