No, coding standards bicker about such frivolous things as whether to use _, m, or m_ for member variables. Just pick one and stick with it. Arguing over one or the other is both useless and utterly stupid.
Well, by definition, you've just created a coding standard.
We often just start out using the standard of someone who has thought it through.
Crockford for JS, Microsoft for C# and Google for Java.
If someone raises a complaint, we do consider it but then the onus is on the developer to justify why it should be changed and that means the developer has to have thought out his/her idea, which is what you really want to begin with.
If it's something as trivial as marking members with "_" or "m_" then it will be a non starter due to,as you said, it just doesn't matter as long as your consistent.