Actually looks like they have a 69322 for 3913, 3913LS and 3913NL, 3953, 9mm and a 69332 for 3914, 3914LS and 3914NL, 9mm. The Service pack without the mag spring is the same for both so I think the different numbers for Service Pack II for the LS is because of the 7 round magazine as opposed to the 8 round for the 3913.
Springs for SMITH & WESSON NUMBERED SERIES Semi-Auto Pistols
When I re-did the springs on my 3913 I used the 69311 Service Pack, which is the same as the 69322 Service Pack but without the magazine spring.
When I replaced my springs I had a brand new green colored S&W recoil spring from Brownells and the Wolff recoil spring did feel a little stiffer than the S&W but not enough to cause any problems. I tried them both and left the Wolff one in, since I was replacing everything else with Wolff springs.
Dave