Fuel relay part numbers .. 300e

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I just bought a fuel pump relay for my early 86 300e.. the -up to -a### whatever..
its the 9 pin 002 545 27 05.
What i got was an 003 545 24 05, the ten pin later model. The part is marked with the 002 part number. Is there any chance this is interchangable and that the 10th pin is just unutilized when used in an early 86 300e?

I know it sounds silly, but they claim that electronic parts are non refundable, and i'm sitting on a 70 dollar core charge and a 70 dollar relay, want to get my money's worth.

Almost a blessing, as i've found one for 40 bucks.. but i've already got this one.