Well brass is a strange substance and undergoes a process of "dezincification" at which piont the metal is significantly weaker. in lay mans terms "corrosion".
not wanting to start a debate over it. just don't want an perdantic comment to boost confidence in the bottle and as a result be filled.
dezincification is very hard to calcutae as it depends on a huge range of factors such as water purity PH levels, the composition of the brass, how when and where it was manufactured, thread lock if used would have a large impact on the rate of the "corrosion" process.
bottom line, DON'T fill it! Brass
DOES "corrode"
Taf.