Tube transmitter plate current meter question
Yes. That 3n3 to ground ought to shunt a lot of RF away from the meter.

Then, there's nothing like a mechanical moving coil meter for acting as a low pass filter, reading the DC correctly, however much AC there is imposed on it. If that's what you mean by a 'sweep meter'.

If I'm not reading 'sweep meter' correctly and it is an electronic meter, then an RF bypass directly across it would be a good idea as well.