Yes, according to the documentation, braces in comments should be ignored.

However, the parser is confused by unbalanced braces in comments.

Here's a classic case that turns up occasionally during development:

  proc asdf { args } {
    # if { first draft complex condition } {
    if { final simplified condition } {
      do something
    } else {
      do something else
    }
  }

Sourcing a file with the above comment inside the proc will produce:

  missing close-brace: possible unbalanced brace in comment