Removing Gamo Rubber Fore-End Grips?

I tried a search, but came up empty. I have a Gamo 640 rifle and want to take the action out of the stock. The plastic stock design is/was used in a wide range of Gamo rifles, and it has a pair of rubber grips on either side of the fore-end that cover up the two forward action screws.

The grips have rubber buttons that snap into holes in the sides of the stock. The rifle is about 15 years old, and I don't want to rip the buttons off if the rubber has gotten tired/hard over time.

I was thinking of applying soapy water or silicone oil so the buttons would pop out easier.

Does anyone have any tricks for dealing quickly & cleanly with this?

Thanks!
 
If you ever need to replace the spring and piston seal I’d recommend the E3650 spring and Tesla seal from experience. Also good candidate for a GRT trigger blade and polished sear contacts. Also it should be super easy to at least put a piston sleeve in. You’ll see a slight reduction in velocity but i found it helps tame the recoil a good deal. 
 
Well, life is what happens when you are busy making other plans... I finally got around to taking the rifle apart this evening. I gently warmed up the rubber bits with a heat gun, and had no trouble pulling the handguard bits off.

From the condition of the screws, it appeared to have been taken apart by the previous owner at some point. All the screws also had threadlocker on them. That strikes me as a pretty good idea, but I was wondering if the factory did that, or it was just the last guy who was inside?

Thanks to everyone for all the suggestions & have a great Holiday!