if the darn thing is not overloaded (great big coil, wrong/ no ballast)
and is a good quality piece, it should not "leak goo."
hell, it was back in the '70's when i converted my rr to electronic--before there ever was such a thing as mopar performance or "kits."
i ran these in both my rr and my mopar powered fj-40 for several years, and never once thought about having "goo" come out.