Help with some GitHub Magic - MAME 0.185

I wasn’t sure exactly where to post this question, so apologies if it’s in the wrong spot.

I’m interested in compiling a MAME core from the latest available from github, but I want to replace the MAME source code with a specific MAME version (0.185, although I think it would be good if this were possible with whatever version people are interested in).

I want to do this so that the core I use is compatible with the romset I have, and also take advantage of any changes to the libretro side of the core that are made with fixes, etc. that aren’t specific to the MAME source code.

R-Type has provide some general guidance in trying to do this here. But I have tried in vain to make this happen - I’m fairly certain the issue is my lack of knowledge in github commands.

Is there anyone interested in the same thing that is familiar with github and the appropriate git steps to merge these two code bases together? Any guidance on the process would be appreciated!

@zachmorris What about working with mame2016? (based on MAME 0.174)