Can the 41-902 spark plug and the 41-933 be used interchangeably?

Here is why I ask this:
I have a set of 6 41-902 plugs.
I recently acquired a 2000 LeSabre with the 3.8 series 2 engine which specs the 41-933
The specs that I could find for the plugs say they are both double plat, heat range 14, same thread length and type.
I would rather not have to buy another set if I don't have to.

The correct spec for the spark plugs is 41-921

They are not the same and there'* a reason for the difference.

What is the difference?

resistance/capacitance and heat range.

I'd use what the manual says to use. It'* once in 100,000 miles and the rear plugs are a pain to get to so totally worth doing it right.

How many miles are on your LeSabre?

144,000 miles. Once done, it'll never need to be done again.