Yeah I really don't know. I'm trying to remember what I was told.
The worst sources of information on gun laws... in no particular order, they're all pretty much equal:
The guy at the gun shop
The customer at the gun shop
A "gun nut" friend
A "gun nut" that a friend knows
With a few exceptions - Internet forums.
There are some good forums out there, but even excellent sites like Calguns, don't take it at face value. Listen to the guy who explains the law, and provides you with the section in the penal code covering it.
Also remember, that which is not forbidden is permitted. The penal code does not cover what is legal, unless it is an exception to something that is illegal, Example: High cap magazines are illegal UNLESS they were acquired prior to the ban.
Pistol grips, flash hiders, telescoping and folding buttstocks... they may all be mentioned in the code, BUT check the context. If the context indicates "semi automatic", then pump, bolt, and lever action firearms are not covered by the section.
Even here in Commiefornia, anything goes on pump/bolt/lever unless it's an SBR/SBS/AOW, or prohibited ammo such as tracers or other incendiary.