I think this has to start with new versions or updates.
For older builds you can very easily use your build date year month day, 20150315 = first publicly seen MPCNC. With that is is very easy to see how long that build has been around…but for me that build lasted about 3 days. I swapped parts nearly daily for the first few months.
The easiest public tracking way to do it would be a public thread. At some threshold your build can be posted with a picture and any info you want to add, but no other commentary, then you get that number.
So if I start a MP3DP Repeat thread and post a picture of my build, I would get Repeat#1, or primo#1, 525#1 etcetera. Plugin in and scripts slow down the server and require troubleshooting occasionally, and I am fighting to keep them at a minimum. The BBpress forums were a nightmare to maintain because of all the necessary plugins.
Unless there is another easy suggestion. I will start that and see how it goes.
I am all for getting a number and having some sort of record of builds, but it really can’t take a lot of “desk time” as that is at a very high premium for me.