We, wife and I, have 2 WSM rifles. One is a 300 model 11 purchased in 2001. Left hand action/bolt. it is my rifle. The other is the 270, model 16, right handed. Not sure how old it is; s/n G485755. Stainless action and barrel.
Spent some more time with rifles last night. I was wrong about the center feed. The 270, as the LH 300 are stagger feed. Here are a couple pics of the bolts:

The left hand bolt is on the left, the 270 bolt with a slightly longer bolt head is on the right.

Here are the bolt faces:

The 270 bolt is on the left and appears to have a smaller firing pin hole.

If that stock 308 head would work on the 270wsm bolt and in the action I'll take it. Hopefully the pics are enough to answer that question.

As a side note, my goal with this 270wsm to 284 change is to have a rifle with somewhat less kick than the wsm. I'm thinking that goal may not be noticeably achievable but We will worry about that after we get a workable 284 rifle.
Thanks to all.