The bases fit perfectly and I had several guys at the club look at it also. Seems to be a good fit. The one near the butt end is lower than the one in front of it and you can't switch them around, the holes only match up in this position and the directions say levers on the opposite of the bolt. The scope on the tasco is a little rought to pull in and out, but the Bushnell goes in and out perfectly and match nice and flat. Guys at the club seem to think it fits good. They just conclude it's the wrong bases or I'm going to have to shim the back way up and I'm not sure I am confortable doing that.
The Cabel's site says, "Interarms Howa 1500
Reversible Front Base (Rem. 700 Spacing)" and this makes me think Howa changed the configuration, but maybe I'm reading that wrong. I didn't buy these from Cabela's - they have it as Item number: IE-710517 and I'm not sure what that means on the Leupold box, where the one I have says 51711.