I'm looking at the errata... and the table entries... it's showing 6P AP+2.
p. 174 Compiled Tables
The following weapon entries should list an AP of +5 (per the updated flechette rules): Raecor Sting (p.174), Ares Viper Slivergun (p.175), Remington Roomsweeper w/ flechettes (p.175), Mossberg AM-CMDT (p.176), Remington 990 w/ flechettes (p.176), Street Sweeper (p.176).
No mention of the gun or a damage code change on the chart.