The split locking bolt makes it easier to break the action since Contenders manufactured once the design was changed were made to break one side slightly before the other side, spreading the effort. Lots of the problems I see people having with lock-up issues and stuck actions have to do with trying to use a solid bolt barrel on a later action. The answer is to swap out the solid bolt and install a split bolt.
All of my frames except my stainless frame lock up fine on my solid bolt barrels, so I relegate my stainless frame to my carbine barrels which all have split bolts. All four of my blued frames are from '79 to '81 vintage and so far have functioned flawlessly with either the solid or split bolt. Later vintage frames are more likely to be incompatible with solid bolts from what I've seen. I have absolutely no experience with the G2 however, so I cannot comment on it.
Curtis
P.S. There are quite a few fellows here who are more knowledgeable than me (Ladobe, Hopalong, 30 Herrett and others), so maybe someone else will chime in shortly.