I just went through all my downloaded photos and photos in Staufer's books of the M1. Here are the configurations:
- Modernized headlight/generator position, footboard pilot, short tender
- Modernized headlight/generator position, slotted pilot, short tender
- Modernized headlight/generator position, solid pilot, long tender
- Modernized headlight/generator position, slotted pilot, long tender
- Original headlight/generator position, footboard pilot, short tender w/doghouse
- Original headlight/generator position, slotted pilot, short tender (looks like w/doghouse)
- Original headlight/generator position, footboard pilot, short tender
- Original headlight/generator position, slotted pilot, short tender
- Original headlight/generator position, slotted pilot, long tender
Anyway, there is photographic evidence of all possible configurations. Unfortunately, most had no dates.
The pictures of the tenders with the doghouse were interesting. There was definitely one with the footboard pilot but not clear enough to say the one with the slotted pilot had one.
For the next catalog I would really like to see a version with the modernized headlight/generator position, footboard pilot, and short tender (with or without the doghouse).