I've just sent this to a parts/numbers guru like no other; SPECIAL K is his name and he'll see into it.

In the meanwhile, that Canadian piece looks a little leaner in the center straight portion hence the lighter weight. The ends look to be beefy as the originals.
I had taken my stock center link like that long ago and jigged it onto a stand and then cut off the ends at the same points on both sides. I turned the end legs down on a lathe and then slipped a chrome-moly hollow tube of certain thickness and strength and plugged tig welded it together. I then ran a complete bead of weld on the surrounding seam to close it up.
Took off 2 pounds.
The stockers weigh 5 pounds.

I believe BondoBob on here also makes them the same way and his workmanship by far is better than mine.

In the meanwhile, I'll see if Special K jimmies in on here or at least gets back to me direct.