You can look at the published data here: https://skywater-pdk.readthedocs.io/en/main/rules/device-details.html#v-pmos-fet where each transistor has a row ILKN* or ILKP* (that I assume comes from e-test data). However, this value is not the transconductance coefficient as the value is declared to be in units of log(A), so it's related to transconductance but I'm not entirely sure what it is that's being measured.

Okay, I guess the BSIM model defines the mobility coefficient u0, and from the SPICE models looks like it is typically 0.03 for nFETs and 0.01 for pFETs (units of V^-1). You can calculate K' from K' = u0 * Cox.