<VV> Top swap?

[hugo at aruncoaches.co.uk]

How easy is it to take a convertible top off one car & fit it to 
another? I have a donor car with an almost new top which I would like to 
fit to the one I'm rebuilding (both 1964's). I'm looking at a row of 
bolts on the inside under the rear window - If I undo them & unbolt the 
frame it should be simple enough to fit the whole top/frame assembly to 
my other car, shouldn't it? Or should it?! (I have taken the outer rear 
trim strip off).