Jim,
I had these at home to get ready for packing and shipping this week, so I weighed one. It weighs at 31.1 grams. These are the Buffalos that do not have the new laser-made hologram.
Now, for the attraction issue: The date I bought these was last September of 2014, following some garage sale collecting of Brass/Copper and selling it at the local scrap metal yard. (I more than doubled my money...and turned those dollars into twice the silver.) The 10 rounds each came in a AMPEX clear plastic envelope.
So, memory is part of the problem, the "attraction" I saw is now seen as something I see and feel that's different when I get down to the nitty-gritty of it. The 2"x2" plastic envelope has a double ply clear plastic that is folded in the center. I grabbed the empty flap and let the silver round hang straight down. As I passed the magnet in front of it, the coin moved. If I move the magnet up close to the coin, it seems that is a slight attraction, but not anything close to a quick jerk and clear "Chink" sound if it was a steel washer.
If I move the magnet up and down, the clear envelope and round will move, the faster I move it the more restriction I feel. So, it's an induction feel rather than a magnetic feel... The magnet is so strong, I can move the magnet up and down up to 3/4" away from the round and it will barely move Buffalo, but so does the 2015 ASE coin I kept out.
So, I can't tell you if these Buffalos are true .999....they magnetically behave as the Eagle coin. I may not return these coins, after all. What's your thinking?
Bill