Can VxRails vcenter for vsphere be used to upgrade existing vcenter instance?

Hello,

I have a customer with an existing vcenter deployed at their primary data center using poweredge servers with IX storage on the backend.  They are interested in purchasing VxRail 2 node clusters for remote data centers and using their existing vcenter to manage it, however, in order to do that they need to upgrade their vcenter to vcenter standard.  When building out the VxRail quote, I found a line item for vcenter for vpshere.  Does anyone know if this line item will allow them to upgrade their existing vcenter?  If not, is there another way we can sell them the upgrade license?