The column lock keys can be found on ebay, original with "Vespa" stamped on them. or at least they could a few years ago. Just looked, price has gone way up.
https://www.ebay.com/str/klassickeyz
63V fits the GS column lock (not yours) (same as ilco 997x y6)
I think the R63V fits yours.
An oldschool locksmith can cut a key to fit the lock, and would likely have a blank that is compatible or close enough.