I would cut the mounting lug off if it hampered "Y" axis movement. I've ran Bridgeports for over 30 years and I don't think there has been one time that I had to mount the vise in the "X" axis. And as stated above, you could always clamp that end.
If there is enough room to cut a groove through that end, then if it is ever mounted in the other axis, you could use a short toe clamp instead of clamping on top of the stationary side.