I think you're 100% correct about that. My flawed memory does recall cloaking D-7's, but I'm sure those were their Romulan counterparts, likely from
Enterprise Incident.
It never made sense why Klingons would operate under cloak, anyway, with their obsession over fighting honorably. Further post-TSFS retconning inferred that Kruge and his crew were actually starting to go insane from operating under cloak for so long, it having a deleterious effect on Klingon physiology, along with substandard engineering from warp core radiation exposure. Which is also why he took prisoners and acted "dishonorably" in combat, at least by 24th century standards, and risk open war with the Federation by going so deep into their territory. He clearly wasn't entirely all there. Perfectly played by Christopher Lloyd, I might add, by clearly inserting some "Reverend Jim" DNA into the character. "Put 'em on screen".