I have a set of 40-60 taking up space, I think they are aluminum, you would need the proper brake discs to make them match up with the 40-281 setup. These 40-60 have a weight of 6.31 lbs stamped on them.

I was going to set these 40-60 up for an extra set of tires, then a set of 40-281 came up for sale and I used those.

I paid $700 US for them , I would sell for that plus shipping.