Syncronizing Data on Samsung ATIV S with Windows Phone 8.1 Update 2 [8.10.15137.148] After Reflash

[Exotic Hadron]

Howdy,

I am using Samsung ATIV S with Windows Phone 8.1 Update 2 [8.10.15137.148].

I started with reflashing the phone to GDR3 ROM and have NOT added my Microsoft account on the first start of the phone. Afterwards, I had to add my account to update the phone to the latest build (I needed to install PfD (Phone for Developers) app).

Finally, when all updates are obtained, I am want all my text messages and contacts to be obtained from the cloud.

The question is: if I enable backup and synchronization now, after I've used the phone for some time, wouldn't it OVERWRITE the data replica in the cloud?

1. I've had like 100+ text messages and 100+ contacts backed up to the cloud.
2. I reflashed the phone.
3. I did not specify my Microsoft account upon the first start of the phone after reflash.
4. I used the phone for some time receiving text messages, adding new contacts WITHOUT having backup enabled.
5. Now I enable the backup: will I get my data that I had before reflashing, or the phone will backup the current state on first synchronization effectively flushing all my old data?

Thank you.