I picked up a brand new 28" John Deer bar (oregon made) for $18 shipped and only had to mill out the slot a little for it to fit my 925 and it works great.
The main thing is how wide the boat tail is. If its two narrow then it can cause interferance with the bar plates as Mike g mentioned,or cause a thrown chain.
If its too wide it will cause problems with the way the chain leaves and rejoins the bar going round the sprocket.
The slot can be made to fit the studs in various ways.