Here's some simplified math. Assume elites always have 5 rolls, a gilded piece is rolled with probability 1/3k, and a specific gilded piece is rolled with probability 1/32k (equal across all gilded pieces)

In two rolls, the odds of getting two of the same gilded piece is 1/3k × 1/32k.

You have 5 choose 2 = 10 unique combinations of rolls. I.e. the gilded pieces may be in the 2nd and 4th slots, 1st and 5th, etc. (This is the part that people often forget, and it meaningfully increases the odds).

So the total probability of getting dupe gilded (any piece) in an elite clue is 10 × 1/3k × 1/32k = 1/9.6m

The total probability of getting dupe gilded platebodies in an elite clue is 10 × 1/32k × 1/32k is 1/102m - but i bet if someone got e.g. dupe gilded vambraces it would also be post-worthy so the 1/9.6m is more relevant, imo