I bought my first G1 on 10/27/2022.
Here are the custom stock dimensions:

G1: CSMC G1 12 Gauge Shotgun 32" Barrels
Monte Carlo Dimensions *14 7/8" x 1 3/8" x 1 3/
8" x 2"* *1/4" cast Off*
*Pachmyr Decelerator D752*

The second high-grade has the same dimensions and should arrive this month.