To my count, 641, 644, 645, 651, 652, 664 is very likely to be DF-41 brigade and 647 is a potential candidate. You are right that they might not be fully operational but the estimation won't change that much in overall warheads count.
The main indicator is the 23m garage to house the 21m DF-41.
For example, 652 brigade garrison here.
View attachment 109135
Yumen 120 silos, Hami 110 silos, Ordos 90 silos.
DF-26/27 could deal with regional nuclear demand and it doesn't count in arm control meanwhile DF-31 definitely will be counted as launcher/missile in arm control and not very potent on MIRV and survivability.
Question regarding these missile base !!
In the even of a US first strike, would all the base housing ICBM be taken out ?
How to deal with this ?