Sorry it didn't work out-but you've got to go with your vibe.
He was advertised on Craigslist by a husband and wife who actually have both parents. They had kept him and another litter mate for their adult son who works in the oilfield. The lady was having to take care of him and other dogs,mind she said it was too much for her. Her son works nights in the oilfield. The couple were very nice and knowledgeable about Bulldogs. I did not get the impression he had been abused. I think it was just a new situation and he was probably anxious. Poor guy.if you felt there was no aggression behind lefty's actions, it just might be a case of an under-socialized dog being taken to a new place, with a new dog and new human for the first time.
what is the story behind lefty, if you don't mind me asking? history of neglect? abuse?