Originally Posted by 2manybikes
No.
Not if you have different length cranks, different pedals, different q factor, different seat post set back, different shoes, shoes with the cleats set differently, different orthotics in the shoes, lots padding in your shorts or not etc.etc. From year to year some saddles with the same name get changed, and the name remains the same.
Even if the seat tube angle is the same lots of things can throw off the way you sit on the seat, your leg angle can be more forward, backwards, or your legs can be open or closed more, changing how your sit bones hit the seat.
Using the identical saddle on a different bike may not work just because the saddle is the same.
I doubt whether riding bow-legged as opposed to knock-kneed will make alot of difference in how sit-bones contact the saddle. They don't have ball-joints like the femur-hip socket. Sitbones can only be rotated as part of pelvic tilt, which can be different on separate bikes and adjusted. As to padding, 2mm of compressed material probably won't be noticeable either. I'm assuming, based on the limited info provided, that the shoes, cleats and orthotics, etc, are all good.
I might ask, are the bikes in question made of the same frame material? Are the chain stays the same length? The bike itself may be transmitting road shock more than the other one.