If you're looking for the sight mount that goes on the gun, I believe its the weaver 429M. But if you have some where, where you can take your gun in. I would recommend doing so.
I had some bad luck with my savage. I spoke to 4 different people at gander and I finally had to bring the gun to them. And they still couldn't figure out what would fit. I finally had to look it up on my phone while the two guys working there watched in awe.
I would double check on each package, because I also found #24 and #82 for the H&R/NEF.