Questions Commerce Connector to Big Commerce Store

Forum, 

I have a general question for anyone with CommConn experience. When running the first sync of info, either import or export, does the primary system override data in target system? I.E., our current primary system for stock items is Big Commerce. All of our descriptions, meta data, images, etc. are being controlled from the BC side. The CommConn only allows export from Acumatica -> BC. We have a custom built integration that places orders in AC, so the SKUs in BC = Inventory IDs in AC, and some customer data is brought over as well. My worry is that when we make the Stock Item entity live, AC will find the SKUs in BC and override all the work we have done to input meta data and images. At some point, I will figure out how to export the items and data from BC and update them in AC. 

Thanks!