Broadcast Sheet / Fender Tag Engine Codes

Great thread. Thanks to the web, the dealer order form, and the window sticker, I've been able to completely decode the fender tag of my 1976 Dart Custom except for M37.

I'm pretty sure it has something to do with the tail panel because of codes M36 and M38 (Rear Bumper Periphery and Decklid Finish Moldings), but not knowing exactly what is driving me a little crazy. I've turned the web inside out and every single decoder I've found is missing that sequence.

Anyone familiar with M37?