It'd be an odd asymmetrical shape if that truly was a rear view. I chalk it up to TOS not showing the perspective properly and say they're the same ship, only with golden glowing shields activated in "Mudd's Woman"
I guess it's quite possible the original artist intended the pointy end to be the front. Or that the glowing shield(?) was obscuring it's true shape. IIRC our first look at a Klingon battlecruiser was a similar golden blob smudge thing.