Just to confirm for anyone who may be wondering, I ordered the one that SAR1 posted the link to at G&R Tactical. I was a little concerned because the "SP" part number listed on G&R's site is different from the "SP" part number listed on SAW's site.
It is in fact the same part and is what the OP is looking for.
It wasn't cheap, though. The part is $40, but G&R has a minimum order of $50. So I threw in a Colt 30-rounder as well ($17). Shipping is another $10 (they shipped my box via UPS). If you're an Ohio resident, sales tax applies as well.
So you're looking at
minimally $60 for the lever (I ended up spending almost $72, but I tell myself that I got a "free" Colt 30-rounder
), but it's correct and - unlike SAW - it's currently in stock and a little less expensive than SAW.
FWIW.
ETA: And yes, the "click" is very well defined, but not hard to rotate.