I've had this piece for a long time and it is very hard to capture the markings due to the thick peppery glaze but it proves who made the MP (Missouri Pacific) marked insulators. I have several G.P.Co. and MP marked beehives (except for the skirt marked white MP beehive) and the cable style but this is the only piece that has both markings. On the skirt it is marked G.P.Co. and on the dome where circled is a faint MP. You really have to stare at it to see the MP even with strong light but it's there. The only thing I can think is they either had a marked G.P. or MP and needed a piece for one order or the other. Although it could have been someone being creative. Hope you enjoyed these photos. Take care stay safe and be well to all.