It really depends on the barrel. A barrel that tapers after the chamber may benefit while a bull barrel with very little taper after the chamber may not. Typically, I'll not bed the chamber area until after I've shot the rifle with normal bedding. If I dont feel any vibration in the fore end, I leave it but if I do, then I'll bed the chamber area and it often cures it. The goal is to not allow the stock to interfere with the normal oscillations of the barrel. If you feel the vibration in the fore end then there is interference which may reduce accuracy. Please notice that I've not made any hard statements. I've done so because every rifle is different and in as much not every technique will apply equally.