Won't fit without some modification. The barrel lug hole is not in the same place in relation to the hinge point. The Sidekick frame is shorter, therefore the forend is longer.
If you are ordering from H&R/NEF, just get the Huntsman synthetic forend. I'm sure they would still have them in stock.
Another option would be to buy a can of spray on bed-liner and paint the wood forend with it, keeping it out of the barrel channel of course. It will look like a synthetic stock, and only you will know the difference.
