A GL reader writes to say that the owner of Barrio, the much blogged about new Mexican restaurant on Seventh Avenue at Third Street in Park Slope (if the food lives up to volume of the blog coverage, it’ll be a winner), will be opening in about ten days, which would put D-Day around April 16. In addition, the owner says that the mystery building next door on Third Street “is finally in preparation to be completely renovated.” There is no evidence of building permits for 497 Third Street being filed yet, however.