Michael:

That might have been me ...

... and you're right: the Mould's I got from Brownells was for the #1S, although I'm not clear why one of others couldn't be made to work.

The Mould's is very nice because in addition to the extra mounting options to solve eye-relief issues, the bottom edge of the rear base is positioned approximately .250" from the front edge of the receiver - so as the barrel heats up from firing there's no contact occuring between the receiver and the mount so as to effect accuracy or change POI. Much better than Ruger's factory set-up.

Also, if you call Brownells, they can give you the specific contact information for the manufacturer of a product they carry or have recently carried even if discontinued. Way back, I got the phone # of a company from Brownells for another product I'd been trying to track down.