Depending on how your TT was driven, the gears might be fine, or not. A lot of cruising at low engine speeds and / or accelerating hard from low engine speed might have damaged the gears.
No way to tell except to take the engine apart. Or, with road tires, drive along a concrete wall. If your bike makes the sound of a dive bomber, your gears are finished. No nobblies, as they make the same sound :-)
The gears on 3AJ and later models indeed were better, but not bomb proof.
If your bikes behaves normally I would not worry. Just start thinking about replacement of the gears if the noises start. And, change oil regularly, choose your sprockets to have a reasonable engine speed at cruise speed, ie abt 4200 rpm / 100 km/h.
Search this forum, lots of facts and opinions to be had.