I don't think there are any good kits for that set. If you read many of the carb rebuild threads, you'll discover there really aren't many good kits for any of these carbs. You're better off just getting any needed parts individually. If you do a careful teardown, you shouldn't need many things. The float bowl gaskets can usually be saved if you're careful removing the bowls. The proper choke housing gasket can be difficult to find but there's no need to remove the choke housing in the first place. If you think you must, and fuck the gasket up in the process, it's your own fault. The choke can be cleaned out by just removing the plunger from the housing - no need to disturb the housing.
The carbs may need new butterfly shaft seals but those are only sold separately, they don't come in any of the kits. There are no o-rings in that year BS38.