New 'bootleg' arcade games missing

Ran Update All the other day, and saw a message that said that some new games were available due to a new core, specifically Elevator Action Bootleg. Normally the Update All takes care of downloading any games I've got arcade cores for but this doesn't seem to be working. I've checked the settings for Update All - I've got the Coin Op collection turned on, and also the Arcade Cores database. Any advice would be much appreciated!