Since the gas port will already have been drilled for the .308, and there is no bolt work to do, and if the external barrel profiles are the same I can't see any problems. Just make sure you have the proper receiver wrench for that action. Note that if headspace is OK you are good. If it is short, you can ream the chamber (is the barrel new short chambered or is it a take-off?). But if it is a take-off and headspaces too long, you can't set the barrel back, you will have to play with bolts until you can get the headspace right.
My inclination would be to try the .308 barrel and if things work, OK. If not, then just swap the barrel back and try to trade for a 100 in .308.
BTW, make sure you use a regular barrel vise and receiver wrench; don't try to screw the barrel on or off using the gas cylinder housing for purchase.
Jim