My two TSC silver duckwing OEGB are very small as well. The ones I hatched from the breeder are smaller tho.I wasn’t alive in the 80s but my fawn, lavender and porcelain hens much larger than my silver duck hen. All 4 are hatchery stock but my little Chipmunk (silver) is so tiny compared to them. I have noticed that show OEGBs are a lot smaller.
Edit: my hatchery stock fawn boy is also much larger than my home bred blue boy.