Did the GOP cost Rick Saccone the election?

A glossy mailer was sent out by Speaker Paul Ryan’s Congressional Leadership Fund Super PAC which was sent to selected Democrat voters in this special election in PA. It says in big letters: Thank you Conner Lamb for OPPOSING Gun control laws. Another one says, Democrat Conner Lamb says new gun laws not necessary to control violence. Did this decision by the GOP cost Rick Saccone the PA election?

BREAKING: Paul Ryan’s PAC Elected Democrat Conor Lamb