We just acquired an '83 27' Excella. The automatic change over regulator was mounted about a foot above the tongue inside the cover, with a hole in the front of the cover to see the "flag" when a bottle runs dry. The hole is located behind the tongue jack, so the "flag was hidden from sight. It looked like a factory installation. The PO just lived with the situation. He let a bottle run dry, then changed over to the other, not using the automatic feature of the regulator. I moved the regulator up to the top of the bottles and bought a new hose at the local RV supply. While I was at it I put on a new regulator and upper supply hoses.
Will all be better now.