Vintage Dirt Bike Q & A

Does anyone out there know if a 82' CR 250R DG pipe will fit a 81' Elsinore CR 250R? Saw a guy on here trying to sell his 81' Elsinore CR 250R with a DG pipe but needed to know if he had to mod it or if it was a straight bolt on. DG only lists a pipe for the 82' CR 250R. Honda parts manuals have 2 different numbers meaning two different pipes?.....not always. Case and point, when you go to the parts break-down on either 81' or 82' CR 250R under the muffler (pipe) it automatically lists the muffler (pipe) for 81' and 82' listed together. But if you veiw them separately you'll find different part numbers under the different years. Somebody please clear this up. Can a 82' CR 250R pipe fit and bolt right on to a 81' Elsinore CR 250R?????