If the saddles cannot be moved far enough forward there are a couple of things to look at:
1) The saddle adjusting screws are not long enough. (Sorry! Bit obvious really but it had to be said!)
2) The pass through holes are trapping the strings preventing the saddles from going any further forward.
If the latter is happening, it may indeed mean that the bridge has been installed too far back. However, it may be possible to fix this, without visible damage to the guitar body, by removing the bridge and doing some careful redrilling of the base plate and modifying the saddles.
A good diagram always helps - I found this one for a GOTOH GTC12 unit at the following link.
http://www.g-gotoh.com/international/?btp_product=gtc12 Although I haven't had any specific experience of GOTOH bridges or 12 string Burns, I have done others.
It looks as if modifying the saddles would be quite tricky on this unit.
Dave