To ascertain which HO has happened, we can use PLMN information to check which PLMN(MME) you are connected to.
-> PLMN information comes in the broadcast information in SIB1.
In the UE logs we can check the PLMN information when the UE is attached to source eNB and then
-> Check the PLMN information of the target eNB which we can check when UE has made the non contention based RACH, again in the SIB1 message.
Now two scenario can happen:
If the PLMN in SIB1 in source eNB is NOT same as that of target eNB then their MME is different.
Since MME is different so X2 HO cannot happen and in this case only S1HO can happen.
If PLMN in SIB1 in source eNB is same as that of target eNB then their MME is different.
Here in this case we cannot identify from the UE logs.