Interesting, didn't know the T-28s were "dodgy" - ex Moroccan weren't they? If memory serves, I saw one in Fort Lauderdale several years later, so presumably they resolved the issue.
Reminds me of the three ex-Zaire AF examples that pitched up at Biggin in late '77 - bit ignorant I was then, thought they were some species of T-34! Well, I was young...