Can Anyone Identify These Strips?

[JGug1]

I spoke with the manufacturer of the Flint Tanks. He said that there is a "weak" point in the models made before '74 (?). If tip tanks are put on later models, they are not required. He also said that the '73's do have a "weakness" at that point but that Cessna had not found it problematic and requiring a fix. To clarify, the tip tanks make the wing more vulnerable in the earlier models. Apparently not so in the later models. 337's were found plenty strong in Vietnam.