I have done one bedding job. Still have the rifle. It is a Winchester Model 70 in 300 WinMag. Three to four inch shooter before, 3/4 to 1 inch shooter now.
In answer to your question, I did a pillar bed in conjunction with an action bed "at the same time". I bought some items from Brownell's:
Pilot Drill Bit - designed specifically for pillar bedding (makes the hole straight in line with the existing screw holes.
Action Bedding Screws - longer with "T" handles for pulling the action into the bedding.
The Pillars - I went with aluminum.
Brownell's "Steel Bed" - their claim is that this epoxy compound comes with a quarter pound of powdered stainless steel (looked like it to me). They say once set, it can be milled on a lathe. I don't know about those claims, but it worked great for me.
I hogged out the recoil lug area and around the action - also for two inches ahead of the barrel, then re-drilled the two action screw holes. I put two layers of painters tape on the front and sides of the recoil lug, and two layers ahead of it on the barrel. I also used painters tape along the top edges of the stock. Painted the metal with release agent, rolled the pillars in the mixed "steel" epoxy (to get epoxy in the pillar's grooves) and inserted them. Thinking back, I believe I used a Q-Tip to coat the inside of the pillars with release agent. Then used a wooden stick (tongue depressor) to fill in the hogged out areas of the stock and recoil lug slot, and put the wood and metal together. Used the T-handle action screws to pull the action down snug and let it sit for a couple of days. Didn't need to wait that long, just had other stuff to do. I loosened the T-handles a few turns then rapped them with a plastic mallet. The action popped free and I cleaned it up then reassembled everything. The bedding looks like a single piece, including the pillars. Went to the range and was really pleased.
So, yes - there is epoxy around the pillars. I strongly suggest using the Pilot Drill bit. It opens the action screw holes enough for the pillars and epoxy. Brownell's is a great source for stuff like this.
Hope this helped.