Wrong pilot jet kz650 vm24

Rejetting some carbs i had and noticed someone had changed the pilot jet but they do not look like stock jet and have a strange number just curious if anyone knows the size the one I took out is on the left an original is on right I believe the number reads 6740 on the jet it appears to be about a size 15 just want to make sure

Should be a #15 for a stock airbox & pipes. I'm curious how you know the pilot size if the pilots are stamped 6740?

I held the 15 and the other jet up to a light and looked through both it looked like a 15 but it is hard to tell the bike did have a 4 into one and pods I usually jet to 110 main and 17.5 idle jet these had 135 mains and this oddball idle jet I'll just order the 17.5 and not worry about it