The database dates back to 1958, and offers a virtual treasure chest of information for history buffs such as myself.
Back to Betsy, a category 5 recertification would not be totally implausible; its 941mb central pressure would be suspect though. However, considering that Betsy was no where near its peak strength at either landfall, there is really no precedence for such an upgrade.
Hurricane history and climatology is a really great thing to get into, and I would encourage you to foster your interests in this regard.