Can a relay use both a flyback diode AND resistor for voltage suppression?
I assume you have looked at the Bosch data on wiring the relay.

You will notice from that data that the relay coil (Pin 85-86) is NOT polarity sensitive. This is probably the reason they used a resistor and not a diode in the unit.

I also assume you have some reason for needing a diode suppressor on the coil ...possibly because you are driving the coil from a BJT or FET rather than a simple switch.

The data (on page 7) actually shows one schematic where they added a diode exactly as you might require:

 

You can put the diode across the resistor without concern, but you have to be conscious of the polarity you used in your wiring (which pin 85 or 86 is wired to 12 V positive). The diode cathode must ALWAYS go to the positive coil terminal you used.