Well 'hap', decide for yourself!

My main project CB-Emu is based on MESS 0.175 (and started even earlier), and that was long before you or Sandro jumped in to the chess emulations.
At this time most of the chess devices in MESS didn't work at all, and I've spent a lot time (and probably also knowledge) to get them running (and creating artworks).

For the later versions (0.190 and 0.215) of MessExtra/MessChess you're absolutely right - here the main work has been done by you and Sandro, and of course we all are very grateful for your work!
But also for these versions I still had to do a lot of work: implementing these new engines in the old CB-Emu version, writing chess plugins for them, and especially making a full ready-to-use package for normal users, which won't want (or won't even be able) to compile the MAME sources by themselves, find the necessary ROMs and configure the MAME/MESS system correctly to use these chess emulations at all.

So 'am I an emulator programmer grandmaster'? Well, I don't know ...

Regards,
Franz