YES....IF the action or barrel is sitting in a uneven pressure bed the results will be the same as a wooden stock.....it might just be more consistantly inaccurate in different conditions over a wooden stock that can swell or warp......some of the upper end metal bedding block syn stocks do better when a thin coat of bedding makes the metal contact the action 100%....and if the stock doesn't have pillars then try to install them.....they seem to make tunning much easier in ones that I have used them.......and lets you torque the stock bolts consistantly to test bedding changes.....good luck and good shooting!!
Soft synthetic and rubber stocks are almost impossible to bed and get them right. A good stuff synthetis stock will bed well, but not the cheap ones or the rubber ones. I would not even waste the time doing it. If you need better accuracy, it would be best to go with a different stock. Bedding works best in something that is stiff already. I have bedded a few cheap synthetic stocks, and gained a little, but not much. If your stock tends to be leaning to the right, and your taking material out of the stock for bedding, it will keep moving right on you.