Sorry Robert
Can't help you any further. Most production lists I have seen differ somewhat, but none I have used so far makes any mentioning of a batch 150050-150237.
There are other A-5 oddities such as aircraft in what seems to be an 151xxx range as well. Can't identify them either. See your own 151xxx range above.
No idea if the G-2s actually received new plates or not, but one source says the re-designation was in October 1943.
If Andrew Arthy or Gerhard Stemmer read this, I would like to see them take a stab at this....
. Anyone else would also be welcome of course.
Cheers
Stig