Did any one of them apologize for their pro-gun stance?

No, they did the opposite:

http://www.politico.com/magazine/story/2017/06/14/what-happened-the-last-time-a-congress-member-was-shot-215263

"On Sunday, the day after Giffords was shot, it was already established that the shooter, Jared Lee Loughner, had carried only one gun. The fact that he had fired 33 rounds provided the basis for what would come next. 'The only reason to have 33 bullets loaded in a handgun is to kill a lot of people very quickly,' said Senator Frank Lautenberg (D-NJ). 'These high-capacity clips simply should not be on the market.'"

(snip)

"The response in the legislature in Giffords's home state was decidedly different. On the Monday after the shooting, a state senator pushed forward an already introduced bill to allow community college faculty members to carry concealed weapons on campus. To the senator, and his Republican colleagues, the logic behind the proposed law was as unassailable as Lautenberg's effort to legislate for a smaller clip. Loughner's community college professor had already told reporters that he'd been reluctant to face the whiteboard while Loughner was in his class, fearing that his student might shoot him while his back was turned."

(snip)

"That split between what members of both parties thought were reasonable reactions to Giffords's shooting extended to the floor of the House. On the Wednesday afterwards, as newly-elected Tea Party colleagues lined up to sign a condolences book that would soon be delivered to Giffords, they also explained why new gun-related legislation wasn't necessary at all. By then, reporters had discovered that Loughner had twice been diagnosed with paranoid schizophrenia. That revelation broadened the conversation to include greater funding for mental health, another concept that was rejected by House Republicans. 'In California, we had a special income tax for mental health funding,' Representative John Campbell told a reporter from Slate. 'It's since been rescinded, since we ran out of money!'"