Here is what I've learned...
Someone told me that the Sear's peds came with 12mm carbs.
The only way to tell for sure is to removed the intake and inspect the intake opening on the head.
If it is round then 12mm was stock.
If it was square, then 14mm or 15mm was "normal"
Mine was square, a trapezoid actually.
Therefore the 14mm cabs I have are correct.
However, I'm still having a hard time finding 14mm carbs, so I'm going with 15mm.
I'll be jetting it smaller I'm sure because I'll be reusing the 14mm intake.
Plug chops will tell me for sure and I'll let you know the results as they come!