If you replace the stock with one contoured for a heavy barrel but leave the factory barrel on for now it won't hurt anything. Worse case scenario it may look a little strange but it will definitely be floated.

As far as the action work goes another option to consider is Stockade Guns (308) 432-5114. They will true and time your action, and can install a barrel if you choose.

Not trying to start WW3 here but I have dealt with both SSS and Stockade and will never use SSS again. In my experience their products are decent at best and their customer service/support is absolutely laughable. Every dealing I've had with Stockade on the other hand has been outstanding. Their products and the quality of work is second to none and their service/support is unreal. Kevin Rayhill (owner of Stockade) is a great guy to work with and has at times talked me out of things that would have made him more money. Do what you will but its something to consider.