This is a great offer and whether or not they take you up on it I hope they sort this soon. It's ridiculous to have a website like this not on https.
FWIW, vBulletin doesn't just store your password in md5 but its approach is known to be obviously weak. Eg.
https://www.troyhunt.com/data-breach...etin-and-weak/
This forum is at least on 3.8.7, but given the footer says 2013 who knows when it was last patched or if it's even still supported by vBulletin.