The 7 year old rebuild question all comes down to how it was stored. If it didn't get moisture in it and get rusty, it is good to go. I have installed millitary surplus engines 15 years old that started on the 2nd or 3rd revolution. No issues. But they were carefully packaged for storage and shipment.
In this case, I would ask the community here if the quality of the reman was good in their experience.
As far as it sitting a long time, I would pull the glow plugs and spin it over until there was oil pressure, and the fuel system was primed, the reinstall glow plugs and fire it up!