How do I find the U-Boot source and build options exactly as it is in the prod version of BBB?

When booting up I see this message for the SPL version:

U-Boot SPL 2013.04-dirty (Jul 10 2013 - 14:02:53)

And a few lines later for the 2nd stage:

U-Boot 2013.04-dirty (Jul 10 2013 - 14:02:53)

Obviously the code is here: U-Boot / U-Boot · GitLab

But I don’t know how to determine:

a) Exactly what tag/commit was used
b) Exactly what build options were used

Is there any way to find out at all please?

I presume from the boot log this might be a good, the 2013.04 tag would be a good starting point: Prepare v2013.04 (d10f68ae) · Commits · U-Boot / U-Boot · GitLab

However, the fact it say ‘dirty’ suggests to me it’s some sort of patched or custom version.

Best answer is located here:
http://www.crashcourse.ca/wiki/index.php/U-Boot_on_the_BBB#BBB-specific_U-Boot_from_current_Git_tree