How do I remove only the buttstock body from a California-compliant M4 collapsible stock?

[PattonjW]

I have a California-compliant Benelli M4 with the OEM collapsible stock. I am NOT trying to make the stock collapsible, and I am NOT trying to remove the recoil tube or pistol grip assembly.

My goal is to remove the buttstock body (the plastic stock portion) from the recoil tube/rail assembly. While investigating, I found and removed a set screw inside the stock body that appears to have been used as part of the California compliance modification. However, the stock body still does not slide off.

I believe the stock I have is the "European Version" OEM Benelli M4 collapsible stock (Part #70132). For those familiar with the OEM Benelli collapsible stock, what is the correct procedure for removing only the buttstock body from the recoil tube? After removing the set screw, should the stock slide off by depressing the release button and pulling rearward, or is there another retention pin/block that I should be looking for?

I've attached photos of the stock. Thak you in advance for any suggestions.