If its possible I would migrate your data again, this time make sure the ID's match old with new. Once that is done then it should be a easy job to 301 redirect each property from old to new, with the data not being matched your forced to write a lookup table to translate if you want to do a seamless migration.
You dont say if you have any coders to hand to do this work but assuming you do I would have thought there must be some link between he 2 data sets even if its the images, if this is the case then you could query the data to do the matching for you.
Without knowing more on the structure its a bit hard to say which is the best route but either getting a lookup table or re-importing the data I would say is the key here.
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