The general consensus is that the 350 only (print group 2 subjects) distribution began in early 1910 and I also believed that was accurate.
I recently discovered this clipping in a November 18 1909 North Carolina newspaper. Buggs Raymond is a 350 only print group 2 subject.
T206 350 only The_Evening_Index_Thu__Nov_18__1909_.jpg
Now I don't consider this ironclad proof unless I find more information to support it but if the newspaper information is accurate then some of the 350 only subjects distribution must have started in October or November of 1909 and at $2.50 "old Buggs" must have been as sought out as Honus and Ty at the time.
With 202 subjects there would have been several different sheets it's possible that they started printing and distributing a couple of 350 only sheets at the end of 1909.
There are 34 subjects with the same or similar back configurations as Buggs Raymond (11 of the 34 weren't printed with Sov 350 while the rest were) besides that they all have the same exact back configuration which differs from the rest of the 202 subjects.
* = Sovereign forest green no print
*Adkins
Armbruster
Beckley
Bescher (port)
Butler (there's a two name T206 with Raymond at the top)
Carrigan
Clancy
*Dessau
*Dorner
*Engle
Ferguson
*Hayden
Howard, Del
Knight (port)
Krause (pitching)
Kroh
*Laporte
Merritt
*Milan
Moeller
Moran, Pat
Moriarty
*Mullen (port)
O'Brien
O'Neil
Perring
Phelps
Randall
Raymond
*Ritter
*Schirm
*Snodgrass (batting)
Thielman
Young, Irv