This morning I've stumbled upon this doubt to which I couldn't find a clear answer.
I intuitively myself that yes, it does preserve validity because as long as you don't change the premises the conclusion should not change.
Transposing the premises does not change the validity of the syllogism. This action does alter the normal format of a syllogism, where the predicate of the conclusion appears in the first premise (the major premise). But validity is unaffected.
(1) All emeralds are green.This gemstone is an emerald. Therefore this gemstone is green.
(2) This gemstone is an emerald. All emeralds are green. Therefore this gemstone is green.
Example (1) shows the usual order of the premises. But both are valid.
What you are referring to is the mood and figure of a syllogism. Yes the order does matter. Consider an A A A in the fourth figure: it is invalid via Venn diagram but reversing the premise order allows validity.
If what you state is true I should be able to change the order of the premises and still not change validity without any exceptions. If anyone finds a syllogism that is valid as written and after the transposition of the premise order the validity disappears you know your method is not valid. Validity requires 100% results that do not vary.
Consider this example: All women are human beings. All human beings are mortal beings. Therefore all mortals beings are women. Invalid as written & Not sound fourth figure and mood A A A. Commits a formal fallacy. Know which one?
All human beings are mortal beings. All women are human beings. Therefore all women are mortal beings. Valid and sound in the first figure and mood A A A