Question about Signings

Probably a silly question but I’m going to the NYC fan event tomorrow and, as an audio listener, the only thing I have DCC related for signing is a copy of the Book 1 AIT USB “Cassette”.

I’m a little concerned that the usual Black Sharpie won’t really show up on any of the packaging art.

Do Matt and Jeff usually have silver sharpies with them for signings, or is that something I should pick up before “just in case”?