Just finished my last marker light.
My original had two bulbs with the old metal base bulbs,( the ones that come apart when you try to twist them out of the socket). The old bulbs fit into a metal retainer that was spring loaded. They did not make very good contact so they were intermittant at best. Most of them would fall apart as soon as I touched them.
The new marker lights have a plastic housing that accepts the little all-glass bulbs, ( like the bulbs that go into yard lights ). These also have two bulbs and are very bright.
The new lights look just like the originals that I removed.
The manufacturer is PM and they are sold at both camper world, ( expensive) and Wally world, (cheap).