Since it's Gallup we're looking at here, I'm guessing more than 53% of those polled supported the president's proposals. Based on the November elections, Gallup's track record hasn't exactly been stellar.
Check out the last three numbers. The only participants who didn't support common sense, and rather mild, ideas to protect people from gun violence were non-Hispanic whites, conservatives, and Republicans. Everybody else did.
And just to sweeten the ol' pot, Americans are down on Republicans in general, but the Democratic Party has a net positive rating.