There are no regulartory limits to the use of procurement dollars for initial spares.  Typically, initial spares are purchased to sustain a program for a period of two years to allow the supply support system to capture usage data and begin the support actions needed to maintain system readiness.

However, there may be program, PEO, or service policies that limit/dictate the use of procurement funds for initial spares.  Recommend that your request be staffed thru your comptroller office to your PEO or service HQ for disposition and further guidance.