Both carbs are Nikki..
I ordered a new one this morning..
The reason I have an old one is because about three years ago before I understood and worked on lawn mower engines myself we to it to jacks power equipt after I had tried everything that was suggested by a mower tech and they replaced the carb with a new one and that lawn tractor ran just fine after that..
I couldn’t find but one 3 letter number and I think one additional number on the carb, so I looked it up on the Briggs online store and got a part number..