What to do is get a tube of #2 black perma-tex and coat one side of it and I don,t think you,ll have a problem then.It is best to replace them but in your case I think it will work out ok. The old D6 esp. the 8 & 9 U series had a bad habit of seeping on the outside area of the gasket on the left side so een a new gasket I always coated it with the #2 perma-tex and remedied the problem.Also put a thin coat on one side of lots of diesel head gaskets other than the D6s to help with any leakage as some had a problem esp. if the head or block had a little roughness on them.
I have reused many head gasgets .I f it is a copper gasket heat it up with a propane torch untill it smokes not red hot or you might burn it .This softens aneals the metal .I have never tried a steel gasket this way.