I'm going to let Kurt comment on the transmission and axle stamps, but they both look good to me. And if that's the case, then congratulations my friend, you have an SS-350!
Going by the numbers, the axle "pumpkin" was cast on May 12th, 1968 and then assembled on May xx, 1968. (You can't see the day, but the code is BS and that indicates a 3.31:1 gear set, which was standard on the 350 engine. You can also see the E for Eaton Posi under that). I would assume the axle was probably assembled in mid to late May, 1968, which is perfect for an early July (07A) car built at the Van Nuys plant.
The transmission was assembled on June 19th, 1968, and has your partial VIN stamped on it, so again, if it's a factory stamp and not a restamp (which I believe is true), it's original to the car and another indicator that it started life as an SS-350.
Can you get a more close-up picture of the transmission stamps? Like I said, they look good to me, but a better picture would confirm that.
And I've fixed your picture of the "pumpkin" casting date (see attached). You can now clearly see E128 (May 12th, 1968).
Ed