Using parts we already own

CA Robotics is planning on using linear bearings we already own from past years to provide motion along a bar.
Does anyone know if it is allowed to use parts we already own, if we can find equivalents in the MSC catalog, and subtract, say, the most expensive price from the allowed limit?

Thanks.

You can use parts you already own, but you must list them at their fair market value, per rule K3.