I've bedded a LOT of Mausers without the spacer/pillar, but the tang does need support, otherwise the action can bend easily, because the tang isn't all that stiff. Epoxy bedding will do the job as well (and often better) than the spacer.
It's difficult to temporarily shim-bed the front end of a 98 Mauser action to test whether free-floating can help, because the front action screw is in the middle of the recoil lug. This was common with many actions back then, including the 1903 Springfield, Arisaka, 1917 Enfield, Winchester Model 54 and others, and is the reason for the common belief that the rear of the barrel has to bedded along with the recoil lug.
The period after WWII, when many "war surplus" bolt action rifles could be purchased cheaply, was also when epoxy bedding originated, and those actions did benefit from epoxy-bedding the rear of the barrel.The need to bed the rear of the barrel disappeared when more bolt-action manufacturers placed the front action screw behind the recoil lug, where tightening it wouldn't bend the front of the action. Most modern actions, including the Model 70 Winchester and Remington 700, have the action screw behind the lug, but a few do not, including the Howa and Nosler 48--the reason both often benefit from bedding the rear of the barrel when bedding the recoil lug.
If you really tighten the front action screw of a 98 without some support of the barrel shank, the front end of the action can bend down, causing erratic contact between the bolt lugs and their recesses. So if you do a temporary shim-test of the action, DON'T tighten the front action lug really hard. It should be firmly tightened, but not enough to bend the action.
