These universal "top hat" style Bosch pintle caps were popular on early EV1 injectors from M20s and M30s.  These will fit single or 4 hole injector ports.  A common upgrade to these is the finned style pintle caps (Euro Injectors Part Number 0135).  These can still be used if you want your injectors to look period correct. 
 
Euro Injectors Part Number: 0141
 
*Note: colors may vary due to availability