Any Leica Hood Experts?

Hi there guys,

I'm buying this little lot of cameras from a private seller, and I pride myself on going off of little to no information, but I can't seem to fully identify a particular Leica hood in a picture. It looks like the legendary OLLUX hood, and looks like it might be the same part number (12522) but it's hard to tell due to the low quality of the image. It certainly looks like the OLLUX though. What puzzles me, however, is there seems to be a letter after the part number, an M or H it looks like. Any guesses, experiences, etc with this hood/ the 1st version 35mm lux this may or may not go to? I've attached the image for a better reference. Any help would be so much appreciated!

Thanks in advance!

In the Leica accessory guide 2nd edition, The OLLUX/12522 is for 35 Summilux below SN2166701. Above that 12504 was used.