Anything's possible... without seeing the bags in question it's hard to say if you can adapt them to suit. I imagine if you get back to suit the honda magna they SHOULD fit, assuming things like exhaust pipes, rear shocks, and indicators aren't in the way... also assuming the magna bags are the style you want.
I'd put the brackets on then take them into the shop and see if the dealer'll be nice enough to let you take a few outside to the bike and see how they line up. Either that or take the magna brackets back and get some easy brackets.
Matt
