I have not heard of offsets or lines being available anywhere for any Carleton canoes... (though it is certainly possible someone has taken them off somewhere along the line). Since Old Town still owns the Carleton brand, they may not be thrilled if someone started selling lines...
The Indian Princess is simply a fancy model of their regular canoe (sort of like an Old Town AA grade). You may be able to find someone who owns a Carleton that will let you take lines off. I would think the older the canoe the better the shape, and if you want a pre-Old Town Carleton, look for something built before 1910.
Beaver Fila has an 1927 Indian Princess built by Carleton but sold as an Old Town. It's the 18ft with sponsons painted green on green . He has had it at a number of recent assemblys. It's in the Havre de Grace Maritime Museum until assembly.
Thank you Knubud: I also have an 18 foot Indian Princess with sponsons plus all the old sailing rig. The canoe is presently disassembled and hopefully to move from upstairs in the barn to the shop. Maybe It will be ready for the Assembly in a year or so. I keep looking for the lines - I think it is a very graceful canoe. Thanks again. Ted Michel