I don't fully understand the context of your problem, but maybe I can help.
If you can open up and view your old .gephi file in Gephi, then you can get the old color attributes and move them to a separate column in the Data Lab's node table.
There is a plug-in for the Data Library that will help you. You can find it here:https://marketplace.gephi.org/plugin/recast-column/
Once you install it, if you go to the "More Actions" menu button, you'll see a couple of options in the "Group 3" category called "Recast column," "Get standart," and "Set standart."
This plug-in is enormously valuable because it allows you use Gephi tools to capture node colors and 3-space coordinates in a layout by using the "Get standart" function. (If you're interested, you can generate your own color values or 3-space coordinate values using your own tools or algorithms and then, using "Set standart," you can make Gephi recognize them.)
My guess is that once you have the color values in their own column in the Data Lab's node table, you can then export the node table and use another tool to match up those colors with nodes in your new environment.