Okay, I see what you're saying. But I'm not sure if it's possible to exclude one ship from receiving a shield texture. You'd have to ask a Dev that. But, honestly, I'm not sure why it'd be necessary at all. Just disable the shield visuals, and you're set.
P.S. The JH shield skin is grey-purple, not purple-purple. I should have specified, but it's been a while since I've used it. This noggin of mine is getting old. You're seeing the right skin.
I was hoping to get pass-thru graphics so that I could have both JH shield visuals with hull customizations. The Borg shields allow this, but unfortunately the JH shields do not. Perhaps a future patch will address this, but until then, I'm not holding my breath!